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 releases or expresses creative energy or emotion;
"she had no other outlet for her feelings""he gave vent to his anger"