Operation can refer to medical surgery, a military campaign, or mathematical methods, such as multiplication and division.

Operation comes from the Latin word opus (“work”) and can refer to a whole range of practical activities and work. In driver's education, you learn the proper operation of a motor vehicle. If you’re going to make your lemonade franchise a success, you’re going to have to learn the rules for prudent operation of a business — how to run it — and you’ll also have to figure out the operation of a lemon squeezer.

Primary Meanings of operation

process or manner of functioning or operating
(mathematics) calculation by mathematical methods
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents
a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body
Full Definitions of operation

n process or manner of functioning or operating

“the power of its engine determines its operation
“the plane's operation in high winds”
functioning, performance
Type of:
physical process, process
a sustained phenomenon or one marked by gradual changes through a series of states

n a process or series of acts especially of a practical or mechanical nature involved in a particular form of work

“the operations in building a house”
“certain machine tool operations
Type of:
activity directed toward making or doing something

n the activity of operating something (a machine or business etc.)

“her smooth operation of the vehicle gave us a surprisingly comfortable ride”
Type of:
any specific behavior

n the state of being in effect or being operative

“that rule is no longer in operation
the state of being in good working order and ready for operation
the state of being in operation
the state of an engine or other mechanism that is idling
Type of:
action, activeness, activity
the state of being active

n a business especially one run on a large scale

“a large-scale farming operation
“a multinational operation
“they paid taxes on every stage of the operation
“they had to consolidate their operations
Type of:
business activity, commercial activity
activity undertaken as part of a commercial enterprise

n a planned activity involving many people performing various actions

“they organized a rescue operation
“the biggest police operation in French history”
“running a restaurant is quite an operation
“consolidate the companies various operations
rescue operation
an operation organized to free from danger or confinement
undercover operation
an operation involving secret work within a community or institution
buy-and-bust operation
an undercover operation by narcotics detectives to catch unsuspecting drug dealers
Type of:
any specific behavior

n activity by a military or naval force (as a maneuver or campaign)

“it was a joint operation of the navy and air force”
military operation
Meuse-Argonne operation
an American operation in World War I (1918); American troops under Pershing drove back the German armies which were saved only by the armistice on November 11
Operation Desert Storm
the United States and its allies defeated Iraq in a ground war that lasted 100 hours (1991)
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combined operation
a military operation carried out cooperatively by two or more allied nations or a military operation carried out by coordination of sea, land, and air forces
maneuver, manoeuvre, simulated military operation
a military training exercise
campaign, military campaign
several related operations aimed at achieving a particular goal (usually within geographical and temporal constraints)
naval campaign
an operation conducted primarily by naval forces in order to gain or extend or maintain control of the sea
military mission, mission
an operation that is assigned by a higher headquarters
reenforcement, reinforcement, support
a military operation (often involving new supplies of men and materiel) to strengthen a military force or aid in the performance of its mission
attack, onrush, onset, onslaught
(military) an offensive against an enemy (using weapons)
offence, offense, offensive
the action of attacking an enemy
peacekeeping, peacekeeping mission, peacekeeping operation
the activity of keeping the peace by military forces (especially when international military forces enforce a truce between hostile groups or nations)
amphibious operation
a military operation by both land and sea forces
information gathering
the act of collecting information
psychological operation, psyop
military actions designed to influence the perceptions and attitudes of individuals, groups, and foreign governments
covert operation
an intelligence operation so planned as to permit plausible denial by the sponsor
expedition, hostile expedition, military expedition
a military campaign designed to achieve a specific objective in a foreign country
combat mission
a mission to capture or defend something
search mission
a mission to discover something
search and destroy mission
an operation developed for United States troops in Vietnam; troops would move through a designated area destroying troops as they found them
close support
close-in firing by one unit against an enemy engaged by another unit
direct support
a mission requiring one force to support another specific force and authorizing it to answer directly the supported force's request for assistance
amphibious demonstration
an amphibious operation conducted for the purpose of deceiving the enemy and leading him into a course of action unfavorable to him
ground attack
an attack by ground troops
an impetuous rush toward someone or something
banzai attack, banzai charge
a mass attack of troops without concern for casualties; originated by Japanese who accompanied it with yells of `banzai'
diversion, diversionary attack
an attack calculated to draw enemy defense away from the point of the principal attack
incursion, penetration
an attack that penetrates into enemy territory
blitz, blitzkrieg
a swift and violent military offensive with intensive aerial bombardment
an attack that is intended to seize or inflict damage on or destroy an objective
counterattack, countermove
an attack by a defending force against an attacking enemy force in order to regain lost ground or cut off enemy advance units etc.
bombardment, bombing
an attack by dropping bombs
a large scale offensive (more than a counterattack) undertaken by a defending force to seize the initiative from an attacking force
dirty war
an offensive conducted by secret police or the military of a regime against revolutionary and terrorist insurgents and marked by the use of kidnapping and torture and murder with civilians often being the victims
push back, rollback
the act of forcing the enemy to withdraw
amphibious assault
an amphibious operation attacking a land base that is carried out by troops that are landed by naval ships
intelligence, intelligence activity, intelligence operation
the operation of gathering information about an enemy
black operation
a covert operation not attributable to the organization carrying it out
fire, firing
the act of firing weapons or artillery at an enemy
an attack of machine-gun fire or cannon fire from a low flying airplane
coup de main, surprise attack
an attack without warning
Type of:
any specific behavior

n (mathematics) calculation by mathematical methods

“they were learning the basic operations of arithmetic”
mathematical operation, mathematical process
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the act of changing the arrangement of a given number of elements
the act of arranging elements into specified groups without regard to order
the mathematical process of obtaining the derivative of a function
maximisation, maximization
the mathematical process of finding the maximum value of a function
an operation used in the calculus whereby the integral of a function is determined
exponentiation, involution
the process of raising a quantity to some assigned power
arithmetic operation
a mathematical operation involving numbers
matrix operation
a mathematical operation involving matrices
drawing a figure satisfying certain conditions as part of solving a problem or proving a theorem
relaxation, relaxation method
a method of solving simultaneous equations by guessing a solution and then reducing the errors that result by successive approximations until all the errors are less than some specified amount
an arithmetic operation that is the inverse of multiplication; the quotient of two numbers is computed
multiplication, times
an arithmetic operation that is the inverse of division; the product of two numbers is computed
minus, subtraction
an arithmetic operation in which the difference between two numbers is calculated
addition, plus, summation
the arithmetic operation of summing; calculating the sum of two or more numbers
matrix addition
the addition of matrices
matrix multiplication
the multiplication of matrices
matrix inversion
determination of a matrix that when multiplied by the given matrix will yield a unit matrix
matrix transposition
the interchange of each row of a square matrix with the corresponding column
the construction of a square having the same area as some other figure
Type of:
calculation, computation, computing
the procedure of calculating; determining something by mathematical or logical methods

n (computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)

“it can perform millions of operations per second”
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access, memory access
(computer science) the operation of reading or writing stored information
asynchronous operation
operations that occur without a regular or predictable time relation to other events
auxiliary operation, off-line operation
a operation performed by off-line equipment not under the control of the central processing unit
binary arithmetic operation, binary operation, boolean operation
an operation that follows the rules of Boolean algebra; each operand and the result take one of two values
computer operation, machine operation
an elementary operation that a computer is designed and built to perform
concurrent operation
two or more operations performed at the same time (or within a give interval)
control function, control operation
an operation that controls the recording or processing or transmission of interpretation of data
dyadic operation
an operation on exactly two operands
fixed-cycle operation
an operation that is completed in a specified number of regularly timed execution cycles
logic operation, logical operation
an operation that follows the rules of symbolic logic
monadic operation, unary operation
an operation with exactly one operand
multiplex operation
an operation in which two or more activities are interleaved
parallel operation, simultaneous operation
the simultaneous execution of two or more operations
printing operation
an operation that controls the printing or display of information
lookup, search
an operation that determines whether one or more of a set of items has a specified property
consecutive operation, sequential operation, serial operation
the sequential execution of operations one after another
sort, sorting
an operation that segregates items into groups according to a specified criterion
synchronous operation
operations that are initiated predictably by a clock
threshold operation
an operation performed on operands in order to obtain the value of a threshold function
disk access
memory access to the computer disk on which information is stored
carriage return
the operation that prepares for the next character to be printed or displayed as the first character on a line
floating-point operation, flop
an arithmetic operation performed on floating-point numbers
line feed
the operation that prepares for the next character to be printed or displayed on the next line
majority operation
a threshold operation in which each operand is 0 or 1; output is 1 if and only if more than half the operands have the value 1
new line
the operation that prepares for the next character to be printed or displayed as the first character on the next line
(computer science) the operation of accessing information from the computer's memory
(computer science) the process of storing information in a computer memory or on a magnetic tape or disk
Type of:
data processing
(computer science) a series of operations on data by a computer in order to retrieve or transform or classify information

n (psychology) the performance of some composite cognitive activity; an operation that affects mental contents

cognitive operation, cognitive process, mental process, process
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basic cognitive process
cognitive processes involved in obtaining and storing knowledge
higher cognitive process
cognitive processes that presuppose the availability of knowledge and put it to use
attending, attention
the process whereby a person concentrates on some features of the environment to the (relative) exclusion of others
lack of attention
instinctive knowing (without the use of rational processes)
the process of perceiving
the process whereby perceived qualities of an object are related to past experience
the cognitive process that leads to convictions
categorisation, categorization, classification, sorting
the basic cognitive process of arranging into classes or categories
discrimination, secernment
the cognitive process whereby two or more stimuli are distinguished
acquisition, learning
the cognitive process of acquiring skill or knowledge
memory, remembering
the cognitive processes whereby past experience is remembered
representational process
any basic cognitive process in which some entity comes to stand for or represent something else
the examination of alternative hypotheses
cerebration, intellection, mentation, thinking, thought, thought process
the process of using your mind to consider something carefully
the sequential mental process in which one thought leads to another by association
deciding, decision making
the cognitive process of reaching a decision
a clear and certain mental apprehension
language, linguistic process
the cognitive processes involved in producing and understanding linguistic communication
Type of:
cognition, knowledge, noesis
the psychological result of perception and learning and reasoning

n a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body

“they will schedule the operation as soon as an operating room is available”
surgery, surgical operation, surgical procedure, surgical process
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catheterisation, catheterization
the operation of introducing a catheter into the body
ablation, cutting out, excision, extirpation
surgical removal of a body part or tissue
a surgical removal of all or part of a limb
an operation to repair a damaged blood vessel or unblock a coronary artery
surgical reconstruction or replacement of a malformed or degenerated joint
a minimally invasive operation to repair a damaged joint; the surgeon examines the joint with an arthroscope while making repairs through a small incision
brain surgery
any surgical procedure involving the brain
surgical removal of the testes or ovaries (usually to inhibit hormone secretion in cases of breast cancer in women or prostate cancer in men)
cauterisation, cauterization, cautery
the act of coagulating blood and destroying tissue with a hot iron or caustic agent or by freezing
use of chemical to destroy diseased or malignant tissue; used in treatment of skin cancer
a surgical opening through the skull
the use of extreme cold (usually liquid nitrogen) to destroy unwanted tissue (warts or cataracts or skin cancers)
curettage, curettement
surgery to remove tissue or growths from a bodily cavity (as the uterus) by scraping with a curette
surgical removal of foreign material and dead tissue from a wound in order to prevent infection and promote healing
removal of the outer covering of an organ or part
D and C, dilatation and curettage, dilation and curettage
a surgical procedure usually performed under local anesthesia in which the cervix is dilated and the endometrial lining of the uterus is scraped with a curet; performed to obtain tissue samples or to stop prolonged bleeding or to remove small tumors or to remove fragments of placenta after childbirth or as a method of abortion
surgery performed with electrical devices (as in electrocautery)
enterostomy, enterotomy
surgical operation that creates a permanent opening through the abdominal wall into the intestine
surgical removal of something without cutting into it
wrong-site surgery
a surgical operation performed on the wrong part of the body
surgical removal of an organ (or the contents of an organ) from a patient
surgical removal of the organs within a body cavity (as those of the pelvis)
eye operation, eye surgery
any surgical procedure involving the eyes
surgical procedure that creates a new fenestra to the cochlea in order to restore hearing lost because of osteosclerosis
surgical removal of all or part of the stomach
surgical creation of an opening between the stomach wall and the small intestines; performed when the normal opening has been eliminated
surgical creation of an opening through the abdominal wall into the stomach (as for gastrogavage)
heart surgery
any surgical procedure involving the heart
haemorrhoidectomy, hemorrhoidectomy
surgical procedure for tying hemorrhoids and excising them
surgical incision into the uterus (as in cesarean section)
a surgical procedure that places something in the human body
intestinal bypass
surgical operation that shortens the small intestine; used in treating obesity
surgical creation of an opening between the jejunum and the anterior abdominal wall; will allow artificial feeding
major surgery
any surgical procedure that involves anesthesia or respiratory assistance
surgery using operating microscopes and miniaturized precision instruments to perform intricate procedures on very small structures
minor surgery
any surgical procedure that does not involve anesthesia or respiratory assistance
surgical incision or division of a muscle
surgical removal of the eardrum
surgical repair of a perforated eardrum with a tissue graft
surgical incision into the eardrum (to relieve pressure or release pus from the middle ear)
any surgery that involves the nervous system (brain or spinal cord or peripheral nerves)
operation to bring an undescended testicle into the scrotum
surgical sectioning of bone
surgical procedure that creates an artificial opening for the elimination of bodily wastes
PPP, UPPP, palatopharyngoplasty, uvulopalatopharyngoplasty
surgical resection of unnecessary palatal and oropharyngeal tissue to open the airway; intended to cure extreme cases of snoring (with or without sleep apnea)
surgical removal or all or part of a vein; sometimes done in cases of severe varicose veins
surgical procedure that uses an intense laser beam to destroy diseased retinal tissue or to make a scar that will hold the retina in cases of detached retina
anaplasty, plastic surgery, reconstructive surgery
surgery concerned with therapeutic or cosmetic reformation of tissue
surgical removal of a polyp
surgical removal of part of a structure or organ
surgical procedure in which an incision is made in the nose to drain accumulated pus
surgical procedure in which spinal nerve roots are cut; done (anterior roots) to relieve intractable pain or (posterior roots) to stop severe muscle spasms
sex-change operation, transsexual surgery
surgical procedures and hormonal treatments designed to alter a person's sexual characteristics so that the resemble those of the opposite sex
Shirodkar's operation, purse-string operation
a surgical procedure in which a suture is used to close the cervix in a pregnant woman; is performed when the cervix has failed to retain previous pregnancies
sterilisation, sterilization
the act of making an organism barren or infertile (unable to reproduce)
the surgical operation of cutting a muscle or tendon of the eye in order to correct strabismus
the surgical procedure of manually restoring a displaced body part
tracheostomy, tracheotomy
a surgical operation that creates an opening into the trachea with a tube inserted to provide a passage for air; performed when the pharynx is obstructed by edema or cancer or other causes
organ transplant, transplant, transplantation
an operation moving an organ from one organism (the donor) to another (the recipient)
an operation that removes a circular section of bone from the skull
surgical correction or repair of defects or injuries in the eardrum or the bones of the middle ear
surgical correction of a defect of the palate
a surgical procedure that attempts to restore the function of the vas deferens after a vasectomy
the act of operating on living animals (especially in scientific research)
abdominoplasty, tummy tuck
cosmetic surgery of the abdomen to remove wrinkles and tighten the skin over the stomach
surgical removal of the adenoids; commonly performed along with tonsillectomy
adrenalectomy, suprarenalectomy
surgical removal of one or both adrenal glands
appendectomy, appendicectomy
surgical removal of the vermiform appendix
the surgical fixation of a joint which is intended to result in bone fusion
surgical repair by using tissue from another part of the patient's own body
brain surgery on human patients intended to relieve severe and otherwise intractable mental or behavioral problems
split-brain technique
brain surgery on animals in which the corpus callosum (and sometimes the optic chiasm) is severed so that communication between the cerebral hemispheres is interrupted
a surgical operation that creates an opening from the colon to the surface of the body to function as an anus
surgical removal of the gall bladder (usually for relief of gallstone pain)
clitoridectomy, female circumcision
excision of the clitoris
suction curettage, vacuum aspiration
a method of induced abortion; prior to the 14th week of gestation the embryo and placenta are removed by applying suction to the dilated cervix
surgical removal of an embolus (usually from an artery)
surgical removal of the inner lining of an artery that is clogged with atherosclerosis
surgical removal of a nerve
cosmetic surgery, face lift, face lifting, facelift, lift, nip and tuck, rhytidectomy, rhytidoplasty
plastic surgery to remove wrinkles and other signs of aging from your face; an incision is made near the hair line and skin is pulled back and excess tissue is excised
closed-heart surgery
heart surgery in which a small incision is made (the chest cavity is not opened)
open-heart surgery
heart surgery in which the rib cage is spread open, the heart is stopped and blood is detoured through a heart-lung machine while a heart valve or coronary artery is surgically repaired
surgical removal of the pituitary gland
surgical removal of the uterus
cataract surgery
eye surgery that involves removing all or part of the lens and replacing it with an intraocular lens implant
cyclodestructive surgery
an eye operation that treats glaucoma by destroying the ciliary body with a laser
filtration surgery
eye surgery that opens a passage allowing excess aqueous humor to drain into surrounding tissues; a treatment for glaucoma
an eye operation that treats closed-angle glaucoma by surgical removal of part of the iris of the eye
a surgical procedure that makes an incision in the iris of the eye in order to enlarge the pupil or to treat closed-angle glaucoma
surgical incision into the cornea
LASEK, laser-assisted subepithelial keratomileusis
a refractive surgery procedure that reshapes the cornea
laser trabecular surgery
eye surgery that makes many tiny laser burns in an area that will increase the drainage of aqueous humor
LASIK, laser-assisted in situ keratomileusis
a refractive surgery procedure that reshapes the cornea
a surgical procedure that removes the vitreous humor and replace it with saline solution
surgical procedure that creates an opening from the ileum through the abdominal wall to function as an anus; performed in cases of cancer of the colon or ulcerative colitis
corneal graft, corneal transplant, keratoplasty
a surgical procedure in which part or all of a damaged or diseased cornea is replaced by healthy corneal tissue from a donor
lipectomy, selective lipectomy
plastic surgery involving the breakdown and removal of fatty tissue
plastic surgery to lift or reshape the breasts
plastic surgery of the nerves
reconstructive surgery of the auricle of the external ear
surgical removal of the bony arches on one or more vertebrae
surgical removal of part or all of the larynx (usually to treat cancer of the larynx)
surgical removal of a stone (calculus)
surgical removal of a lobe from any organ of the body (as the lung or brain)
surgical removal of a tumor without removing much of the surrounding tissue or lymph nodes; performed in some cases of breast cancer
robotic telesurgery
microsurgery in which the surgeon performs surgery by manipulating the hands of a robot
surgical removal of a breast to remove a malignant tumor
surgical removal of some or all of the mastoid process
surgical removal of the meniscus of the knee
surgical removal of a kidney
surgical removal of all or part of a nerve
oophorectomy, ovariectomy
surgical removal of one of both ovaries
surgical removal of one or both ovaries and the corresponding Fallopian tubes
surgical removal of an eye
orchidectomy, orchiectomy
surgical removal of one or both testicles
surgical removal of part or all of the pancreas
surgical removal of a lung (usually to treat lung cancer)
surgical removal of part or all of the prostate gland
surgical removal of one or both Fallopian tubes
surgical removal of all or part of a septum (especially the nasal septum or atrial septum)
surgical removal of part or all of the sigmoid colon (usually to remove a malignant tumor)
surgical removal of the spleen
surgical removal of the stapes of the middle ear
surgical interruption of a nerve pathway in the sympathetic nervous system
surgical removal of a blood clot (thrombus) from a blood vessel
surgical removal of the thyroid gland
surgical removal of the palatine tonsils; commonly performed along with adenoidectomy
reconstructive surgery on the penis to repair congenital abnormality or injury
proctoplasty, rectoplasty
reconstructive surgery of the anus or rectum
altering, fixing, neutering
the sterilization of an animal
TURP, transurethral resection of the prostate
removal of significant amounts of prostate tissue (as in cases of benign prostatic hyperplasia)
application of a substance that destroys tissue by freezing it
cautery (destruction of tissue) by heat
surgical procedure that removes all or part of the vas deferens (usually as a means of sterilization); is sometimes reversible
surgical removal of part or all of the vulva
surgical contraception
contraception by surgical sterilization
xenotransplant, xenotransplantation
a surgical procedure in which tissue or whole organs are transfered from one species to another species
Type of:
medical procedure
a procedure employed by medical or dental practitioners

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