Deuterostomia

plural noun

Deu·​ter·​o·​sto·​mia

in many classifications

: a major division of the animal kingdom comprising all bilateral animals (such as the chordates) that lack ectomesoderm and have indeterminate cleavage and a mouth that does not arise from the blastopore

Word History

Etymology

New Latin, from deuter- entry 1 + -stomia

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