What is "to touch bottom"

Bottom \Bot"tom\ (b[o^]t"t[u^]m), n. [OE. botum, botme, AS. botm; akin to OS. bodom, D. bodem, OHG. podam, G. boden, Icel. botn, Sw. botten, Dan. bund (for budn), L. fundus (for fudnus), Gr. pyqmh`n (for fyqmh`n), Skr. budhna (for bhudhna), and Ir. bonn sole of the foot, W. bon stem, base.

1. The lowest part of anything; the foot; as, the bottom of a tree or well; the bottom of a hill, a lane, or a page.

   Or dive into the bottom of the deep.
   --Shak.

2. The part of anything which is beneath the contents and supports them, as the part of a chair on which a person sits, the circular base or lower head of a cask or tub, or the plank floor of a ship's hold; the under surface.

   Barrels with the bottom knocked out.
   --Macaulay.

   No two chairs were alike; such high backs and low backs and leather bottoms and worsted bottoms.
   --W. Irving.

3. That upon which anything rests or is founded, in a literal or a figurative sense; foundation; groundwork.

4. The bed of a body of water, as of a river, lake, sea.

5. The fundament; the buttocks.

6. An abyss. [Obs.]
   --Dryden.

7. Low land formed by alluvial deposits along a river; low-lying ground; a dale; a valley. ``The bottoms and the high grounds.''
   --Stoddard.

8. (Naut.) The part of a ship which is ordinarily under water; hence, the vessel itself; a ship.

   My ventures are not in one bottom trusted.
   --Shak.

   Not to sell the teas, but to return them to London in the same bottoms in which they were shipped.
   --Bancroft.

   Full bottom, a hull of such shape as permits carrying a large amount of merchandise.

9. Power of endurance; as, a horse of a good bottom.

10. Dregs or grounds; lees; sediment.
    --Johnson.

    At bottom, At the bottom, at the foundation or basis; in reality. ``He was at the bottom a good man.''
    --J. F. Cooper.

    To be at the bottom of, to be the cause or originator of; to be the source of. [Usually in an opprobrious sense.]
    --J. H. Newman.

    He was at the bottom of many excellent counsels.
    --Addison.

    To go to the bottom, to sink; esp. to be wrecked.

    To touch bottom, to reach the lowest point; to find something on which to rest.