\"d8Greg`a*ri"n\"91 (?), n. pl. [NL., fr. Gregarina the typical genus, fr. L. gregarius. See Gregarious.] Zool.
An order of Protozoa, allied to the Rhizopoda, and parasitic in other animals, as in the eartborm, lobster, etc. When adult, they have a small, wormlike body inclosing a nucleus, but without external organs; in one of the young stages, they are amebiform; -- called also Gregarinida, and Gregarinaria.
© Webster 1913.