In chess, en passant (french for in passing) describes the capture by a pawn of an enemy pawn on the same rank and an adjacent file that has just made an initial two-square advance.
Learned this during GPU Chess Hackathon in San Francisco
This is a special rule in the game of chess where the capturing pawn (black) moves to the square that the enemy pawn (white) passed over in it’s first move (aka it moved 2 squares forward). This results in the enemy pawn (white) being captured
Wikipedia Link: https://en.wikipedia.org/wiki/En_passant
En Passant is used in Forsyth-Edwards Notation
Embarrassed to say that I did NOT know about this rule until I participated in this hackathon…