Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

protostome

play
noun pro·to·stome \ˈprō-tə-ˌstōm\

Definition of protostome

  1. :  any of a major group (Protostomia) of bilateral metazoan animals (as mollusks, annelids, and arthropods) characterized in typical forms by determinate and spiral cleavage, formation of a mouth and anus directly from the blastopore, and formation of the coelom by splitting of the embryonic mesoderm — compare deuterostome



Origin and Etymology of protostome

New Latin Protostomia, from prot- + Greek stoma mouth — more at stomach


First Known Use: 1959


Learn More about protostome


Seen and Heard

What made you want to look up protostome? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a very small amount

Get Word of the Day daily email!