Vent

n. [Probably from Fr. vent, wind, Pr. vent, ven, Pg. & It. vento, Sp. viento, Lat. ventus.] 1. A small aperture; a hole, or passage for air or any fluid to escape; as, the vent of a cask. Wounds do bleed at many vents. Shak. Long ’twas doubtful, both so closely pent, Which first should issue from the narrow vent. Pope.

2. Hence, specifically, (a.) The opening at which the excrements, especially of birds, are discharged; anus. (b.) (Mil.) The opening at the breech of a fire-arm through which fire is communicated to the charge; touch-hole. (c.) (Arch.) A crenelle or loop-hole. Oxf. Gloss. (d.) (Steam-boilers.) The sectional area of the passage for gases (the calorimeter) divided by the length of the same passage in feet.
3. Hence, figuratively, opportunity of escape from confinement or privacy; emission; escape; passage to notice or expression; publication; utterance. “Without the vent of words.” Milton.

Thou didst make tolerable vent of thy spleen. Shak. To give vent to, to suffer to escape; to let out; to pour forth; as, to give vent to anger. — To take vent, to escape; to become disclosed; to be made public. — Vent-piece, in some fire-arms, a piece of copper containing the vent, and screwed in at the proper position.