sump

noun

1. A hollow or pit into which liquid drains, such as a cesspool, cesspit or sink.
2. The lowest part of a mineshaft into which water drains.
3. A completely flooded cave passage, sometimes passable by diving.
4. The crankcase or oil reservoir of an internal combustion engine.
5. The pit at the lowest point in a circulating or drainage system (FM 55-501).
6. An intentional depression around a drain or scupper that promotes drainage.
7. (Scotland)A sudden or heavy fall of rain; a deluge.

   “then, seating himself thus, he replied to him of the east.—'Sounding sump o' rain Saunders Creeshmeloof—saw ye ever a drap o' rain for eight and forty hours after the bonnie sinking sun that sat sae red and sae lang on the summit of Blackwood hills this blessed afternoon? That starry plow o' thine is […]'”

   “"Me and the lads did it this morn." "It was pouring!" Brody said. "If I was tae stop an activity because of a sump o' rain, I'd never get anythin' done," Finn remarked with a twinkle in his eye.”

verb

1. (intransitive)Of a cave passage, to end in a sump, or to fill completely with water on occasion.

   “We discovered a new passage, but it sumped after 100 metres.”

   “This low passage sumps quickly after moderate rainfall.”