Noun

1. A hole for the escape of gas or air
2. External opening of urinary or genital system of a lower vertebrate
3. A fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt
4. A slit in a garment (as in the back seam of a jacket)
5. Activity that frees or expresses creative energy or emotion

Verb

1. Give expression or utterance to
2. Expose to cool or cold air so as to cool or freshen