sump
/sʌmp/noun
1- a pit or hollow in which liquid collects, in particular集水坑, 尤指：
1.1
- the base of an internal-combustion engine, which serves as a reservoir of oil for the lubrication system（内燃机润滑系统的）集油槽, 油底壳。
1.2
- a depression in the floor of a mine or cave in which water collects（矿井或山洞中的）水窝。
1.3
- a cesspool污水坑。
词源
Middle English （in the sense 'marsh'）： from Middle Dutch or Low German sump, or (in the mining sense) from German Sumpf; related to SWAMP.