Cig is a colloquial shortening of cigarette, from French cigarette, diminutive of cigare, from Spanish cigarro, of uncertain origin (possibly from Mayan sik'ar 'to smoke'). The historical trail runs through cigarro in Spanish. The history must be left partly open, preserving the uncertainty rather than forcing a single unsupported ancestry. Used as a noun, cig now means "an informal shortening of cigarette", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in derived forms such as ciggy and related forms such as cigarette and cigar. That uncertainty is part of the entry: the safest account is the attested form and the limited comparisons preserved with it.