[ awr-nuh-this-kee-uh n ]
/ ˌɔr nəˈθɪs ki ən /


any herbivorous dinosaur of the order Ornithischia, having a pelvis resembling that of a bird.Compare saurischian.


belonging or pertaining to the Ornithischia.

Origin of ornithischian

1900–05; < New Latin Ornithischi(a) (ornith- ornith- + -ischia < Greek ischíon ischium) + -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for ornithischian

/ (ˌɔːnɪˈθɪskɪən) /


of, relating to, or belonging to the Ornithischia, an order of dinosaurs that included the ornithopods, stegosaurs, ankylosaurs, and triceratops


any dinosaur of the order Ornithischia; a bird-hipped dinosaur

Word Origin for ornithischian

C20: from ornitho- + Greek ischion hip joint
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for ornithischian

[ ôr′nə-thĭskē-ən ]

Any of various dinosaurs belonging to the group Ornithischia, one of the two main divisions of dinosaurs. Ornithischians had a pelvis similar to that of modern birds (although birds are not descended from them), in which part of the pubis pointed backwards and parallel to the ischium. They also had a special bone in front of the lower jaw (called the predentary bone), and frequently had armor plating or bony outgrowths of the skull. Ornithischians comprise all the herbivorous dinosaurs except the sauropods, and include ankylosaurs, hadrosaurs, stegosaurs, and ceratopsians. Compare saurischian.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.