any animal with no backbone, for example a worm compare vertebrateTopics Insects, worms, etc.c2无脊椎动物 Word Originearly 19th cent. (as a noun): from modern Latin invertebrata (plural) ‘the invertebrates’ (former taxonomic group), from French invertébrés, from in- ‘without’ + Latin vertebra (from vertere ‘to turn’).