• (n. pl.) A comprehensive division of the animal kingdom, including all except the Vertebrata.
In·ver`te·bra'ta noun plural [ New Latin , from Latin in- not + vertebratus vertebrate.] (Zoology) A comprehensive division of the animal kingdom, including all except the Vertebrata. 
Type: Term Pronunciation: in-ver′tĕ-brā′tă Definitions: 1. A general category of the kingdom Animalia (multicellular animals) including those phyla the members of which lack a notochord; all animals except vertebrates in the phylum Chordata.