FIREWORM Meaning of FIREWORM in English ˈ ̷ ̷ˌ ̷ ̷ noun 1. : the larva of various small tortricid moths that eats the leaves of the cranberry giving the vines a scorched look2. : glowworm Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012