What is the X in X-mas?
"to reduce to charcoal," 1670s, probably a back-formation from charcoal (q.v.). Related: Charred; charring.
programming /keir/ or /char/; rarely, /kar/ character. Especially used by C programmers, as "char" is C's typename for character data. [Jargon File] (1994-11-29)