placoid

[ plak-oid ]

adjective

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

placoid

/ 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

Word History and Origins

Origin of placoid¹

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

Word History and Origins

Origin of placoid¹

C19: from Greek plac-, plax flat

Example Sentences

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

From Fox News

As to whether they represent the remnant of a once present system of epidermal scales, which may have preceded the coating of placoid elements in the evolution of the vertebrate, there is no evidence.

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

But one of the most remarkable weapons of the period was the sting of the Pleuracanthus, another great placoid of the age of gigantic fishes.

From Project Gutenberg