sump oil en · NOUN
Meanings
-
(uncountable) Lubricating oil contained in the sump of an engine; the waste oil drained from the sump at the time of an oil change.
Dirty sump oil is pumped out along a waste oil pipe line to storage tanks by the boiler house, to be used as boiler fuel.
1960 December, “New G.E. Line diesel loco maintenance depot at Stratford”, in Trains Illustrated, page 767: