"to reduce to charcoal," 1670s, probably a back-formation from charcoal (q.v.). Related: Charred; charring.
Entries linking to char
charcoal n.
"coal made by subjecting wood to smothered combustion," mid-14c., charcole, from coal; the first element is either Old French charbon "charcoal," or [Middle English Compendium] Middle English charren "to turn, change" (from Old English cerran) + cole "coal," thus, "turned to coal."