sump

nouns

an oil reservoir in an internal combustion engine
sump
is a type of (narrower)
tank used for collecting and storing a liquid (as water or oil)
reservoir
a well or other hole in which water has collected
sump
is a type of (narrower)
a deep hole or shaft dug or drilled to obtain water or oil or gas or brine
well
a covered cistern; waste water and sewage flow into it
cesspit, cesspool, sink, sump