A cavity is a carved-out space inside something solid like a wall or a tooth. If you have a cavity, you have a hole in your tooth, and it’s time to go to the dentist for a filling. Lucky you.

Doctors sometimes refer to various internal body parts as cavities, such as the "abdominal cavity," which includes the stomach and other hollow parts of the abdomen. You are more likely to hear the word at the dentist’s office, when she finds a cavity, which is a space in your tooth that's been eaten away by decay. Fun! (Not.) Cavity shares the Latin root cavus, "hollow," with the word cave.

Definitions of cavity

n space that is surrounded by something

enclosed space
a cavity or space in something
pocket, pouch, sac, sack
an enclosed space
Type of:
an empty area (usually bounded in some way between things)

n a sizable hole (usually in the ground)

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a sloping pit with a stake in the middle used as an obstacle to the enemy
barbecue pit
a pit where wood or charcoal is burned to make a bed of hot coals suitable for barbecuing meat
borrow pit
a pit created to provide earth that can be used as fill at another site
(golf) the cavity left when a piece of turf is cut from the ground by the club head in making a stroke
fire pit
a pit whose floor is incandescent lava
a pit filled with loose wet sand into which objects are sucked down
a large pit in sandy ground from which sand is dug
a pit over which lumber is positioned to be sawed by two men with a long two-handed saw
tar pit
a natural accumulation of bitumens at the surface of the earth; often acts as a trap for animals whose bones are thus preserved
Type of:
hole, hollow
a depression hollowed out of solid matter

n (anatomy) a natural hollow or sinus within the body

bodily cavity, cavum
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blastocele, blastocoel, blastocoele, cleavage cavity, segmentation cavity
the fluid-filled cavity inside a blastula
central cavity of the gastrula; becomes the intestinal or digestive cavity
any of various air-filled cavities especially in the bones of the skull
locule, loculus
a small cavity or space within an organ or in a plant or animal
a cavity or passage in a tubular organ
a bony hollow into which a structure fits
pulp cavity
the central cavity of a tooth containing the pulp (including the root canal)
cranial orbit, eye socket, orbit, orbital cavity
the bony cavity in the skull containing the eyeball
buccal cavity
the cavity between the jaws and the cheeks
a natural cavity or hollow in a bone
(zoology) the cavity (in birds, reptiles, amphibians, most fish, and monotremes but not mammals) at the end of the digestive tract into which the intestinal, genital, and urinary tracts open
any of various bodily cavities leading to another cavity (as of the ear or vagina)
the part of the thoracic cavity between the lungs that contains the heart and aorta and esophagus and trachea and thymus
middle ear, tympanic cavity, tympanum
the main cavity of the ear; between the eardrum and the inner ear
pleural cavity
the cavity in the thorax that contains the lungs and heart
an enclosed volume in the body
cranial cavity, intracranial cavity
the cavity enclosed by the cranium
amniotic cavity
the fluid-filled cavity that surrounds the developing embryo
greater peritoneal sac, peritoneal cavity
the interior of the peritoneum; a potential space between layers of the peritoneum
bursa omentalis, lesser peritoneal cavity, omental bursa
an isolated part of the peritoneal cavity that is dorsal to the stomach
pericardial cavity, pericardial space
the space between the layers of the pericardium that contains fluid that lubricates the membrane surfaces and allows easy heart movement
a tiny cavity filled with fluid in the cytoplasm of a cell
one of four connected cavities in the brain; is continuous with the central canal of the spinal cord and contains cerebrospinal fluid
a structure resembling a bag in an animal
uterine cavity
the space inside the uterus between the cervical canal and the Fallopian tubes
nasal cavity
either of the two cavities lying between the floor of the cranium and the roof of the mouth and extending from the face to the pharynx
cavity forming the upper part of the pharynx
cavity formed by the pharynx at the back of the mouth
the lower part of the pharynx
blind gut, caecum, cecum
the cavity in which the large intestine begins and into which the ileum opens
tubular cavity
a cavity having the shape of a tube
armpit, axilla, axillary cavity, axillary fossa
the hollow under the arm where it is joined to the shoulder
chest cavity, thoracic cavity
the cavity in the vertebrate body enclosed by the ribs between the diaphragm and the neck and containing the lungs and heart
abdomen, abdominal cavity
the cavity containing the major viscera; in mammals it is separated from the thorax by the diaphragm
pelvis, renal pelvis
a structure shaped like a funnel in the outlet of the kidney into which urine is discharged before passing into the ureter
pelvic cavity
the space bounded by the bones of the pelvis and containing the pelvic viscera
celom, celoma, coelom
a cavity in the mesoderm of an embryo that gives rise in humans to the pleural cavity and pericardial cavity and peritoneal cavity
fossa, pit
a concavity in a surface (especially an anatomical depression)
yolk sac
membranous structure enclosing the yolk of eggs in birds, reptiles, marsupials, and some fishes; circulates nutrients to the developing embryo
umbilical vesicle, vesicula umbilicus, vitelline sac, yolk sac
membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
amnion, amnios, amniotic sac
thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
the outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)
the saclike body cavity of a coelenterate
air bladder, float, swim bladder
an air-filled sac near the spinal column in many fishes that helps maintain buoyancy
air sac
any of the membranous air-filled extensions of the lungs of birds
air sac
any of the thin-walled extensions of the tracheae of insects
ethmoid sinus, ethmoidal sinus, sinus ethmoidales
a sinus of the meatuses of the nasal cavity (behind the bridge of the nose)
frontal sinus
one of a pair of cavities in the frontal bone
maxillary sinus
one of a pair of sinuses forming a cavity in the maxilla
nasal sinus, paranasal sinus, sinus paranasales
any of the paired sinuses in the bones of the face adjacent to the nasal cavity that are lined with mucous membrane that is continuous with the lining of the nasal cavities
glenoid cavity, glenoid fossa
the concavity in the head of the scapula that receives the head of the humerus to form the shoulder joint
glenoid fossa, mandibular fossa
a deep concavity in the temporal bone at the root of the zygomatic arch that receives the condyle of the mandible
hip socket
the socket part of the ball-and-socket joint between the head of the femur and the innominate bone
alveolus, tooth socket
a bony socket in the alveolar ridge that holds a tooth
vestibule of the ear
the central cavity of the bony labyrinth of the ear
saccule, sacculus
a small sac or pouch (especially the smaller chamber of the membranous labyrinth)
heart ventricle, ventricle
a chamber of the heart that receives blood from an atrium and pumps it to the arteries
any chamber that is connected to other chambers or passageways (especially one of the two upper chambers of the heart)
fourth ventricle
an irregular ventricle between the third ventricle and the central canal of the spinal cord
third ventricle
a narrow ventricle in the midplane below the corpus callosum; communicates with the fourth ventricle via the Sylvian aqueduct
lateral ventricle
either of two horseshoe-shaped ventricles one in each cerebral hemisphere; they communicate with the third ventricle via the foramen of Monro
epigastric fossa, pit of the stomach
a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)
bladder, vesica
a distensible membranous sac (usually containing liquid or gas)
one of the small sacs or saclike dilations in a compound gland
a small fluid-filled sac located between movable parts of the body especially at joints
cistern, cisterna
a sac or cavity containing fluid especially lymph or cerebrospinal fluid
pocket, pouch
(anatomy) saclike structure in any of various animals (as a marsupial or gopher or pelican)
cyst, vesicle
a small anatomically normal sac or bladderlike structure (especially one containing fluid)
vestibule of the vagina
the space between the labia minora containing the orifice of the urethra
air cell, air sac, alveolus
a tiny sac for holding air in the lungs; formed by the terminal dilation of tiny air passageways
pharynx, throat
the passage to the stomach and lungs; in the front part of the neck below the chin and above the collarbone
acetabulum, cotyloid cavity
the cup-shaped hollow in the hipbone into which the head of the femur fits to form a ball-and-socket joint
pericardial sac
the membrane surrounding the heart
Type of:
anatomical structure, bodily structure, body structure, complex body part, structure
a particular complex anatomical part of a living thing

n soft decayed area in a tooth; progressive decay can lead to the death of a tooth

caries, dental caries, tooth decay
Type of:
the process of gradually becoming inferior