sump

UK: /ˈsʌmp/ US: /sʌmp/ ,(sump)

WordReference Random House Learner's Dictionary of American English © 2025

sump /sʌmp/   n. [countable]

1. Building a pit, cesspool, etc., in which liquid is collected or into which it drains.

WordReference Random House Unabridged Dictionary of American English © 2025

sump (sump),  n. 

1. Building a pit, well, or the like in which water or other liquid is collected.
2. Mechanical Engineering [Mach.] a chamber at the bottom of a machine, pump, circulation system, etc., into which a fluid drains before recirculation or in which wastes gather before disposal.
3. Mining
   • a space where water is allowed to collect at the bottom of a shaft or below a passageway.
   • a pilot shaft or tunnel pushed out in front of a main bore.
4. Automotive, British Terms [Brit.] crankcase.
5. British Terms a swamp, bog, or muddy pool.

• Middle Low German or Middle Dutch sump; cognate with German Sumpf; akin to swamp
• late Middle English sompe 1375–1425

Collins Concise English Dictionary © HarperCollins Publishers::

sump / sʌmp/ noun

1. a receptacle, such as the lower part of the crankcase of an internal-combustion engine, into which liquids, esp lubricants, can drain to form a reservoir
2. another name for cesspool
3. a depression at the bottom of a shaft where water collects before it is pumped away

Etymology: 17th Century: from Middle Dutch somp marsh; see swamp