Origin: 1325–75;Middle English < Latincombūstus (past participle of combūrere to burn up, equivalent to com-com- + -ūs- variant stem of ūrere to burn + -tus past participle suffix; -b- by misanalysis of ambūrere, another derivative, as am- + -būrere)
late 14c., adj., "burnt," from O.Fr. combust (14c.) (see combustion). Also an astrological term for planets when near the sun; the verb is attested from late 15c.