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Definition of hesperornis
hesperornis
/ˌhɛs.pərˈɔːr.nɪs/
hes · per · or · nis
Plural:hesperornithes
hesperornis Lexical Profile
CEFR
C2
Grade
12
Tier
3
Usage
Rare
• noun
1
An extinct genus of flightless, aquatic, toothed birds that lived during the Late Cretaceous period, native to the marine environments of the Western Interior Seaway in North America.
Example
"The fossilized remains of a hesperornis revealed that these primitive birds had powerful hind legs for diving and lobed toes similar to modern grebes."
• Rhymes for hesperornis
• Nearby Words
Word Origin & Etymology
Coined in 1872 by paleontologist Othniel Charles Marsh from the Ancient Greek 'hesperos' (western) and 'ornis' (bird), referring to its discovery in the western United States.
Usage Trend
Historical frequency of usage in published text.
180019102020
Data source: Google Books Ngram Viewer
Cite this Entry
Wordmom. (2026). Definition of Hesperornis. In Wordmom Dictionary. Retrieved Oct 14, 2026, from https://wordmom.com/dictionary/hesperornis