Palaeechinoidea
plural noun
Palae·echinoidea
Definition of Palaeechinoidea
in some classifications
: a division of extinct chiefly Paleozoic sea urchins having the test usually composed of more than 20 meridional rows of plates that often overlap and jaws always present — compare euechinoidea
Keep scrolling for more
Test Your Vocabulary
The Exceptions Quiz III
-
- Which of these words does not mean "nonsense"?

Test your visual vocabulary with our 10-question challenge!
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Words at Play
Ask the Editors
Share Palaeechinoidea