Merriam-Webster's Collegiate® Dictionary, 11th Edition
VENT
I. verb see: wind
Date: 14th century
transitive verb to provide with a vent,
2. to serve as a vent for , discharge , expel , to give often vigorous or emotional expression to , to relieve by means of a vent , intransitive verb to relieve oneself by venting something (as anger) , see: express
II. noun
Etymology: Middle English, anus, outlet, probably from Anglo-French, wind, draft, outlet
Date: 15th century
an opening for the escape of a gas or liquid or for the relief of pressure: as, the external opening of the rectum or cloaca ; anus , b. pipe 3c, fumarole , hydrothermal vent , an opening at the breech of a muzzle-loading gun through which fire is touched to the powder, chimney , flue , an opportunity or means of escape, passage, or release ; outlet , ventless adjective
III. noun see: bite
Date: 15th century
a slit in a garment, ventless adjective