Although "stool pigeon" is generally used today to mean a
snitch, usually a prison house snitch, it was originally used to mean a tool or person used to lure a criminal into a trap.
The phrase comes to us from the
French, those
dastardly French, who used pigeons to lure
hawks into nets for capture.
While some people contend the phrase origin is as simple as that the French would nail pigeon
decoys to a stool to lure in a hawk, the "
stool" itself does not actually refer to a piece of furniture. Rather "stool" implies a decoy.
Stooling was a term used for
hunting ducks with decoys.