Discovery: A phrase to describe a delayed repartee

Word discovery: “esprit d’escalier” or “wit of the staircase”
Citation: “The Wit of the Staircase”, weblog intro
Usage: From the French phrase 'esprit d'escalier,' literally, it means 'the wit of the staircase' [color font mine]
Meaning: As explained in the weblog intro: “…usually refers to the perfect witty response you think up after the conversation or argument is ended.”
Comments: This actually has a name?
Notes: I haven’t been able to confirm that it is an idiom of French. Do you know? I looked up “esprit d’escalier” and didn’t find a direct translation via the program I used. However, I did verify that “wit” or “humor” are among the meanings for esprit and “staircase” is one of the meanings for escalier. (Usage example: rampe d’escalier means bannister.)

Also, from the title: repartee