What is the X in X-mas?
1856, "put a cap on again," from re- + cap (n.). Specific sense "put a strip of rubber on the tread of a tire" is 1920s. As a shortened form of recapitulate, it dates from 1920s. Related: Recapped; recapping.
: I gave her a quick recap of the incident
To repeat, esp in a summary form; recapitulate; rehash (1940s+)