vent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Forceful expression or release of pent-up thoughts or feelings.
• noun An opening permitting the escape of fumes, a liquid, a gas, or steam.
• noun The small hole at the breech of a gun through which the charge is ignited.
• noun Zoology The excretory opening of the digestive tract in animals such as birds, reptiles, amphibians, and fish.
• noun The opening of a volcano in the earth's crust.
• noun An opening on the ocean floor that emits hot water and dissolved minerals.
• intransitive verb To express (one's thoughts or feelings, for example), especially forcefully. synonym: voice.
• intransitive verb To release or discharge (steam, for example) through an opening.
• intransitive verb To provide with a vent.
• intransitive verb To vent one's feelings or opinions.
• intransitive verb To be released or discharged through an opening.
• intransitive verb To rise to the surface of water to breathe. Used of a marine mammal.
• noun A slit in a garment, as in the back seam of a jacket.

from The Century Dictionary.

• To let out at a vent; make an opening or outlet for; give passage to; emit; let pass.
• To furnish with a vent; make a vent in.
• To give utterance, expression, or publicity to; especially, to report; publish; promulgate; hence, to circulate.
• Reflexively, to free one's self; relieve one's self by giving vent to something.
• noun An inn.
• noun A small aperture leading out of or into some inclosed space; any small hole or opening made for passage.
• noun Specifically— The small opening into the barrel of a gun, by which the priming comes in contact with the charge, or by which fire is communicated to the charge; a touch-hole.
• noun The opening in the top of a barrel to allow air to pass in as the liquid is drawn out; also, the vent-peg with which the opening is stopped.
• noun A hollow gimlet used to make an opening in a cork or barrel, in order to draw out a small quantity of liquid for sampling; a liquid-vent or vent-faucet
• noun In molding, one of the channels or passages by which the gases escape from the mold
• noun The flue or funnel of a chimney.
• noun A crenelle or loophole in an embattled wall.
• noun In steam-boilers, the sectional area of the passage for gases, divided by the length of the same passage in feet.
• noun In musical instruments of the wood wind group, a finger-hole
• noun The end of the intestine, especially in animals below mammals, in which the posterior orifice of the alimentary canal discharges the products of the urogenital organs as well as the refuse of digestion, as the anus of a bird or reptile; also, the anal pore of a fish, which, when distinct from the termination of the intestine, discharges only the milt or roe. See cut under Terebratulidæ.
• noun A slit or opening in a garment.
• noun An escape from confinement, as for something pent up; an outlet.
• noun Utterance; expression; voice.
• noun A discharge; an emission.
• noun Scent; the odor left on the ground by which the track of game is followed in the chase.
• noun In hunting, the act of taking breath or air.
• To vend; sell.
• noun The act of selling; sale.
• noun Opportunity to sell; market.
• To scent, as a hound; smell; snuff up; wind.
• To open or expand the nostrils to the air; sniff; snuff; snort.
• In hunting, to take breath or air.
• To draw, as a chimney, or a house, room, etc., by means of a chimney.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To sell; to vend.
• transitive verb To let out at a vent, or small aperture; to give passage or outlet to.
• transitive verb To suffer to escape from confinement; to let out; to utter; to pour forth.
• transitive verb obsolete To utter; to report; to publish.
• transitive verb obsolete To scent, as a hound.
• transitive verb To furnish with a vent; to make a vent in. a mold.
• noun obsolete Sale; opportunity to sell; market.
• intransitive verb obsolete To snuff; to breathe or puff out; to snort.