n (1) 底，底部(lowest part or point of sth outside or inside)[C，通常sing][N(of)]：at the～of the stairs/the mountain在楼梯/山脚下;at the～of the slope/the wall/the valley/the pile在斜坡/墙/山谷/堆的底部;at the～of the page/the list在书页/名单的最末处;at the～of the steps/one's trouser legs在台阶的最低几级/裤腿边处; at (in/on) the～of the cup/the box/the trunk/the basket/the well 在杯子/盒子/皮箱/篮子/井的底部(上);oars in the～of a boat放在船底部的桨; barnacles on the～of a boat长在船底上的藤壶贝;B～s up! (infml)干杯! 〖同〗base，foot;〖反〗 top，summit，peak;

(2) (海，湖，河之)底，水底(solid surface under a sea， lake or river)[C，the～][N(of)]：at/on the～of the sea/the lake/the river在海/湖/河底;(diver/ship) go/sink to the～(潜水员/船)沉入水底;send an enemy ship to the～把敌船打沉海底;The water is very deep here; I can't touch (the)～. 这儿水很深，我够不着底。〖同〗riverbed，depths;〖反〗surface;

(3) 屁股 (part of the body on which one sits) [C]：fall on one's～摔个屁股墩;smack/spank a child's～打小孩的屁股;

(4) 末端，远处(farthest part or point (of sth)͵ far end (of sth))[C， the～][N(of)]：at the～of the road/the garden 路的尽头/花园深处;down at the～of the meadow在草地的尽头;sit at the～of a long table 坐在长桌子的尽头;

(5) 最(末)(lowest place or position in a class， list， etc)[C，the～][N(of)]：He is always (at) the～of the class in science.他的理科(成绩)在班上总是垫底。Who came～in the exam? 这次考试谁是最后一名? He started at the～(of the ladder)， and worked his way up to success/to become a president. 他从最底层干起，却奋斗成功了/成了总统。Officials at the top make the decisions; men at the～carry them out.上层官员做决定，下层人员去执行。

(6) 起点(因)(the starting point; the cause)[C，the～][N(of)]：Who is at the～of all this trouble/these rumours? 谁是这起纠纷的祸首/这些谣言的制造者?～line 决定性因素;

(7) 套服的下身(lower part of a two-piece garment)[C，通常pl]：pyjama/track suit～s 睡裤/运动裤;

at bottom 实际上，根本上：He pretends to be very bold， but he's really a cowardly man at～.他假装很胆大，实际上却很胆小。

from the bottom of one's heart由衷地：I thank/congratulate you from the～of my heart.我真心感谢/祝贺你!

get to the bottom of 弄清……的原因(真相)：Let's get to the～of this (mystery/matter/problem). 咱们来把这(奥秘/事/问题)弄清楚。

→′bottomless adj 无底的，很深的;无限的，用不完的;′bottommost adj 最低的;

adj 最低(后)的 (lowest or last)：in the～row在最后一排;on the～step of the stairs在楼梯最低一级;the book on the～stack/shelf书架最底层的书;the～button of a waistcoat/rung of a ladder坎肩最底下的扣子/梯子最低一级;the～line on a page一页的最后一行;～prices最低价;go in～gear以最慢档行驶;〖同〗lowest，deepest;〖反〗highest，uppermost，upper;

bottom out (v adv) 降到最低点(vi)：The crisis/recession has～ed out.危机/萧条已达到最严重的程度。House prices have～ed out.房价已降到最低水平。