 Historically, "flammable", "inflammable" and "combustible" meant "capable of burning".The word "inflammable" came through French from the Latin "inflammāre" = "to set fire to," where the Latin preposition "in-" means "in" as in "indoctrinate", rather than "not" as in "invisible" and "ineligible".The word "inflammable" may be erroneously thought to mean "non-flammable".