Quiz: Remember the definition of mal de mer?


[ahr-thruh-dahyuh r] /ˈɑr θrəˌdaɪər/
any of numerous fishes of the extinct order Arthrodira, widely distributed during the Devonian Period, having the anterior part of the body covered by a shield of bony plates.
< New Latin Arthrodira, equivalent to arthro- arthro- + -dira < Greek deirḗ neck, throat
Related forms
[ahr-thruh-dahy-ruh n] /ˌɑr θrəˈdaɪ rən/ (Show IPA),
arthrodirous, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Encyclopedia Article for arthrodiran


any member of an order of extinct, armoured, jawed fishes (placoderms) found in Devonian freshwater and marine deposits. (The Devonian period lasted from 416 million to 359 million years ago.) Early arthrodires, such as the genus Arctolepis, were well-armoured fishes with flattened bodies. They had hollow, backward-curved shoulder spines and may have used the long spines to anchor themselves or to move about on the bottom.

Learn more about arthrodire with a free trial on
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source

Word of the Day

Difficulty index for arthrodire

Few English speakers likely know this word

Word Value for arthrodiran

Scrabble Words With Friends