n.

1. 底；底部；下端[C]
   The bottom of the cup is broken.

   这杯子的底破了。

2. 屁股，臀部[C]
3. （海、河的）底部，水底[the S]
4. 最低下的部分，底层[the S]
   The apples at the bottom of the basket are smaller.

   篮子底部的苹果较小。

5. 远端，尽头[the S] [（+of）]
6. 起点；原因[the S] [（+of）]
   We will get to the bottom of the mystery.

   我们将揭开这个谜。

7. （汽车等的）最低档[U]
8. 吃水线以下的船体[C]
9. 低洼地[P]
10. 持久力，耐力[U]

a.[Z]

1. 最低的；最后的，最下的
   The bottom layer is a mixture of sand and clay.

   最下面的一层是沙和泥的混合物。

vt.

1. 在……上装底
2. 对……寻根究底
   They tried to bottom his motives but failed.

   他们曾想追查他的动机但未成功。

vi.

1. 基于，根据[（+on/upon）]
   Upon what does his claim bottom?

   他提出这一要求的根据是什么？

2. 到达底部；降至最低点[（+out）]
   The recession has bottomed out.

   经济衰退已至谷底。

n.

1. the lowest point or part of something.
   ▸the furthest part or point of something.
   ▸ (also bottoms) the lower half of a two-piece garment.
2. chiefly Brit. a person's buttocks.
3. archaic stamina or strength of character.
4. Physics  one of six flavours of quark.

adj.

v.

1. (of a ship) touch the bottom of the sea.
2. (bottom out) (of a situation) reach the lowest point before stabilizing or improving.