Share this entry

rudist Line breaks: rud¦ist
Pronunciation: /ˈruːdɪst/
(also rudistid ruːˈdɪstɪd)

Definition of rudist in English:


A cone-shaped fossil bivalve mollusc which formed colonies resembling reefs in the Cretaceous period: [as modifier]: rudist bivalves
More example sentences
  • An extinct group of Mesozoic bivalves, the rudistids, became closely adapted to a cemented mode of life: one valve became conical while the other formed a lid.
  • Cretaceous radiations of rudists were apparently initiated during periods of globally high sea level and the Lebanon decapod faunas are a part of this general increasing invertebrate diversity.
  • This member contains abundant and diverse mid-Cretaceous shallow-marine invertebrates, including reef corals and rudist bivalves.


Late 19th century: from modern Latin Rudista (former group name), from Latin rudis 'rude'; for the variant spelling see -id3.

Definition of rudist in:

Share this entry


What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources