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placoid

American  
[plak-oid] / ˈplæk ɔɪd /

adjective

  1. platelike, as the scales or dermal investments of sharks.


placoid British  
/ ˈplækɔɪd /

adjective

  1. platelike or flattened

  2. (of the scales of sharks and other elasmobranchs) toothlike; composed of dentine with an enamel tip and basal pulp cavity

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of placoid

1835–45; < Greek plak- (stem of pláx ) something flat, tablet + -oid

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Researchers in this study also revisited an analysis of fossilized placoid scales, or tiny tooth-like scales that cover sharks, from the megalodon.

From Salon

The fossils discovered include 134 teeth, 61 vertebrae, 23 placoid scales and fragments of calcified cartilage, researchers said in a statement.

From Fox News

An important feature is the complete absence of all trace of the calcified placoid plates which are so characteristic of the Elasmobranchii.

From Project Gutenberg

The remains of fish are as yet confined to the upper part of the Silurian series; but some of these belong to placoid fish, which occupy a high grade in the scale of organization.

From Project Gutenberg

A singular species, rare, but easily recognized by its peculiar, placoid scales, large and firmly embedded in the peridial wall.

From Project Gutenberg