Merriam-Webster Collegiate Dictionary - bottom

 I. noun  Etymology: Middle English botme, from Old English botm; akin to Old High German bodam ~, Latin fundus, Greek pythmen  Date: before 12th century  1.  a. the underside of something  b. a surface (as the seat of a chair) designed to support something resting on it — used figuratively in phrases like the ~ dropped out to describe a sudden collapse or downturn lost millions when the ~ dropped out of the stock market  c. the posterior end of the trunk ; buttocks, rump  2. the surface on which a body of water lies  3.  a. the part of a ship's hull lying below the water  b. boat, ship  4.  a. the lowest part or place the ~ of the page  b. the remotest or inmost point  c. the lowest or last place in point of precedence started work at the ~  d. the part of a garment worn on the lower part of the body; especially the pants of pajamas — usually used in plural  e. the last half of an inning of baseball  f. the bass or baritone instruments of a band  5. ~land — usually used in plural  6. basis, source trying to get to the ~ of these rumors  7. capacity (as of a horse) to endure strain  8. a foundation color applied to textile fibers before dyeing  9. a fundamental quark that accounts for the existence and lifetime of upsilon particles and has an electric charge of - 1/3 and a measured energy of approximately 5 GeV; also the flavor characterizing this particle  • ~ed adjective  II. verb  Date: 1520  transitive verb  1. to furnish with a ~  2. to provide a foundation for  3. to bring to the ~  4. to get to the ~ of  intransitive verb  1. to become based  2. to reach the ~  3. to reach a point where a decline is halted or reversed — usually used with out the team ~ed out in last place  • ~er noun  III. adjective  Date: 1561  1. of, relating to, or situated at the ~ ~ rock  2. frequenting the ~ ~ fish