invertebrate(n = noun.animal) - any animal lacking a backbone or notochord; the term is not used as a scientific classification;
is a kind of animal, animate being, beast, brute, creature, fauna
has parts: foot, invertebrate foot, peristome
has particulars: arthropod, zoophyte, parazoan, poriferan, sponge, cnidarian, coelenterate, comb jelly, ctenophore, worm, borer, woodborer, rotifer, mollusc, mollusk, shellfish, phoronid, bryozoan, moss animal, polyzoan, sea mat, sea moss, ectoproct, entoproct, symbion pandora, brachiopod, lamp shell, lampshell, peanut worm, sipunculid, echinoderm
invertebrate(a = adj.all) spineless - lacking a backbone or spinal column; "worms are an example of invertebrate animals"
Antonym: vertebrate
Destitute of a backbone; having no vertebræ; of or pertaining to the Invertebrata. [1913 Webster]
invertebrate, adj. & n.
--adj.
1 (of an animal) not having a backbone.
2 lacking firmness of character.
--n. an invertebrate animal.
Etymology:
mod.L invertebrata (pl.) (as IN-(1), VERTEBRA)