bot·tom 
(bŏtəm)
(bŏtəm)n.
1. The deepest or lowest part: the bottom of a well; the bottom of the page.
2. The part closest to a reference point: was positioned at the bottom of the key for a rebound.
3. The underside: scraped the bottom of the car on a rock.
4. The supporting part; the base.
5. The far end or part: at the bottom of the bed.
6.
a. The last place, as on a list.
b. The lowest or least favorable position: started at the bottom of the corporate hierarchy.
7. The basic underlying quality; the source: Let's get to the bottom of the problem.
8. The solid surface under a body of water.
9. often bottoms Low-lying alluvial land adjacent to a river. Also called bottomland.
10.
a. Nautical The part of a ship's hull below the water line.
b. A ship; a boat: "English merchants did much of their overseas trade in foreign bottoms" (G.M. Trevelyan).
11. often bottoms The trousers or short pants of pajamas.
12. Informal The buttocks.
13. The seat of a chair.
14. Baseball The second or last half of an inning.
15. Staying power; stamina. Used of a horse.
16. Slang One who is penetrated by another person or is the submissive partner in a sexual encounter or relationship.
adj.
1. Situated at the bottom: the bottom rung of the ladder.
2. Of the lowest degree, quality, rank, or amount: the bottom three teams in the league.
v. bot·tomed, bot·tom·ing, bot·toms
v.tr.
1. To provide with an underside.
2. To provide with a foundation; base: jurisprudence that is bottomed on democratic principles.
v.intr.
Phrasal Verb: To have or strike the underside against something: The car bottomed on the gravel.
bottom out
Idiom: To reach the lowest point possible, after which only a rise may occur: Sales of personal computers have bottomed out.
at bottom
Basically.
[Middle English botme, from Old English botm.]
bottom·er n.