A duct is a pipe, tube, or tunnel through which water can flow. If there's a leaking duct in your kitchen, you may need to patch it or replace it — in any event, you should probably call a plumber.

Liquids can move through a duct, and when the duct is in a person's body, like a tear duct or a pancreatic duct, it has the same purpose — tears, for example, flow through tear ducts. Some ducts aid the flow of substances other than liquids, like the air ducts that blow warm air from your furnace into the rooms of your house. Duct tape, often incorrectly called "duck tape," is tape that's used for repairing ducts.

Definitions of duct
  1. noun
    an enclosed conduit for a fluid
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    a duct that admits air to be mixed with fuel
    air duct, air passage, airway
    a duct that provides ventilation (as in mines)
    an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room
    breather, schnorchel, schnorkel, snorkel, snorkel breather
    air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time
    air passage consisting of a ventilation shaft through which air leaves a mine
    ventilation shaft
    a shaft in a building; serves as an air passage for ventilation
    type of:
    a passage (a pipe or tunnel) through which water or electric wires can pass
  2. noun
    a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance
    “the tear duct was obstructed”
    synonyms: canal, channel, epithelial duct
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    any small opening in the skin or outer surface of an animal
    canalis vertebralis, spinal canal, vertebral canal
    the canal in successive vertebrae through which the spinal cord passes
    ductule, ductulus
    a very small duct
    a small canal or duct as in some bones and parts of plants
    Schlemm's canal, canal of Schlemm, sinus venosus sclerae
    a circular canal in the eye that drains aqueous humor from the anterior chamber of the eye into the anterior ciliary veins
    sinus, venous sinus
    a wide channel containing blood; does not have the coating of an ordinary blood vessel
    lachrymal duct, lacrimal duct, tear duct
    any of several small ducts that carry tears from the lacrimal glands
    nasolacrimal duct
    a duct that carries tears from the lacrimal sac to the nasal cavity
    Haversian canal
    any of the many tiny canals that contain blood vessels and connective tissue and that form a network in bone
    hepatic duct
    the duct that drains bile from the liver
    canalis inguinalis, inguinal canal
    oblique passage through the lower abdominal wall; in males it is the passage through which the testes descend into the scrotum and it contains the spermatic cord; in females it transmits the round ligament of the uterus
    bile duct, common bile duct
    a duct formed by the hepatic and cystic ducts; opens into the duodenum
    pancreatic duct
    a duct connecting the pancreas with the intestine
    lymph vessel, lymphatic vessel
    a vascular duct that carries lymph which is eventually added to the venous blood circulation
    salivary duct
    a duct through which saliva passes from the salivary gland into the mouth
    Sylvian aqueduct, aqueductus cerebri, cerebral aqueduct
    a canal connecting the third and fourth ventricles
    either of a pair of thick-walled tubes that carry urine from the kidney to the urinary bladder
    duct through which urine is discharged in most mammals and which serves as the male genital duct
    canalis cervicis uteri, cervical canal
    a spindle-shaped canal extending from the uterus to the vagina
    umbilical, umbilical cord
    membranous duct connecting the fetus with the placenta
    the lower part of the female reproductive tract; a moist canal in female mammals extending from the labia minora to the uterus
    a convoluted tubule in each testis; carries sperm to vas deferens
    ductus deferens, vas deferens
    a duct that carries spermatozoa from the epididymis to the ejaculatory duct
    ejaculatory duct
    a part of the seminal duct formed by the duct from the seminal vesicle and the vas deferens; passes through the prostate gland
    cartilaginous tube
    a duct with cartilaginous walls
    any of the smallest bronchial ducts; ending in alveoli
    GI tract, alimentary canal, alimentary tract, digestive tract, digestive tube, gastrointestinal tract
    tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination
    lactiferous duct
    ducts of the mammary gland that carry milk to the nipple
    cavernous sinus, sinus cavernosus
    either of a pair of large venous sinuses in the cranial cavity
    coronary sinus, sinus coronarius
    a short sinus receiving most of the veins of the heart; empties into the right atrium
    sigmoid sinus, sinus sigmoideus
    an S-shaped dural sinus on the temporal and occipital bones
    sinus rectus, straight sinus, tentorial sinus
    an unpaired sinus of the dura mater
    sinus transversus, transverse sinus
    a paired dural sinus; terminates in the sigmoid sinus
    sweat duct
    a small duct that conveys sweat from a sudoriferous gland to the surface of the skin
    biliary ductule
    excretory ducts of the liver; empty into the hepatic ducts
    thoracic duct
    the major duct of the lymphatic system
    any of the lymphatic vessels that convey chyle from the small intestine to the thoracic duct
    bronchial tube, bronchus
    either of the two main branches of the trachea
    trachea, windpipe
    membranous tube with cartilaginous rings that conveys inhaled air from the larynx to the bronchi
    the alimentary canal (especially of an embryo or a coelenterate)
    a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass
    type of:
    passage, passageway
    a path or channel or duct through or along which something may pass
  3. noun
    a continuous tube formed by a row of elongated cells lacking intervening end walls
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    a plant duct containing latex
    type of:
    plant part, plant structure
    any part of a plant or fungus
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