I want to know how it works.
It is the difference between the evaluation of the engine's best move, compared to the move you selected, averaged out over the entire game... with one important caveat; in positions where either side has a 5-pawn (or 6-pawn; I'm not 100% sure) advantage or more in the evaluation (not just material), centipawn loss is no longer counted unless it loses that advantage.
A centipawn is 1/100th of a pawn, if your centipawn loss is 100, on average you lost a pawn every move compared to the best move of the computer. It's a measurement to see how accurately you and your opponent played.
