Scavenging
Pronunciation : Scav"eng*ing, p. pr. & vb. n. of Scavenge. Hence
Part of Speech : n.
Definition : Defn: Act or process of expelling the exhaust gases from the cylinder by some special means, as, in many four-cycle engines, by utilizing the momentum of the exhaust gases in a long exhaust pipe.
(Internal- combustion Engines)
Source : Webster's Unabridged Dictionary, 1913