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Definition of placoderm
placoderm
/ˈplæk.əˌdɜːrm/
plac · o · derm
Plural:placoderms
•Adjective:placodermal
placoderm Lexical Profile
CEFR
C2
Grade
11
Tier
3
Usage
Rare
placoderm Game Scores & Validity
Scrabble US
Scrabble UK
WWF
Wordle Guess
• noun
1
An extinct jawed fish of the class Placodermi, prevalent during the Silurian and Devonian periods, characterized by a heavily armored head and thorax made of articulated bony plates.
Example
"Dunkleosteus is one of the most famous and formidable placoderms, known for its massive size and powerful, self-sharpening jaw plates."
• Rhymes for placoderm
• Nearby Words
Word Origin & Etymology
Coined in the mid-19th century from Greek 'plax' or 'plak-' (flat plate) and 'derma' (skin), referring to the protective bony plates covering the heads and thoraxes of these prehistoric fish.
Usage Trend
Historical frequency of usage in published text.
180019102020
Data source: Google Books Ngram Viewer
Cite this Entry
Wordmom. (2026). Definition of Placoderm. In Wordmom Dictionary. Retrieved Oct 18, 2026, from https://wordmom.com/dictionary/placoderm