'Instroke' definitions:

Definition of 'instroke'

From: WordNet
noun
The stroke of an engine piston moving away from the crankshaft

Definition of 'Instroke'

From: GCIDE
  • Instroke \In"stroke`\, n. An inward stroke; specif., in a steam or other engine, a stroke in which the piston is moving away from the crank shaft; -- opposed to outstroke. [Webster 1913 Suppl.]