in passing; by the way used, in chess, of the capture of a pawn which has just taken a first move of two
squares, passing an opponent's pawn that dominates the first of those squares and
that makes the capture by moving to that square
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'en passant'Fr