from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of several groups of extinct primitive jawless fishes of the Ordovician through the Devonian periods in North America and Europe, having bodies that were encased in an armor of bony plates.
from the GNU version of the Collaborative International Dictionary of English
- n. Any of several extinct fishlike jawless vertebrates having a heavily armored body; of the Paleozoic.
from The Century Dictionary and Cyclopedia
- Having a bony skin like a coat of mail; ostraciont, as a fish; pertaining to the Ostracodermi. Also ostracodermal, ostracodermous.
- n. An ostraciont fish, as a member of the Ostracodermi; a plectognath of the suborder Ostracodermi.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. extinct fish-like jawless vertebrate having a heavily armored body; of the Paleozoic
Greek ostrakon, shell; + -derm.(American Heritage® Dictionary of the English Language, Fourth Edition)