bombycid moth bom·by·cid·moth uncommon noun 1. moderate-sized Asiatic moth whose larvae feed on mulberry leaves and produce silk Synonymsbombycidbombycid mothsilkworm moth Related words Broader terms moth Narrower terms domestic silkworm moth Parts Bombycidae WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.