A person who is on the receiving end of gay sex. It is often confused, and assumed that the bottom is submissive, however a bottom can be dominant. (See power bottom)
1) Someone who prefers to take a more submissive role in sexual situations. This definition pertains to the B/D/S/M (Bondage and Domination, Domimation and Submission, Sado-Masochism) scene.
2) A homosexual male who either a) enjoys receiving anal penetration or b) is activeluy involved in being anally penetrated.
1) You can tell she's a bottom because she's wearing a collar.
2) Oh, Jeff is such a bottom. As soon as any cute guy walks past he's on his back with his knees by his ears!