Scute

A scute (Latin scutum, "shield") is a horny, chitinous, or bony external plate or scale, as on the shell of a turtle or the underside of a snake. They are similar to scales, but unlike scales, they are derived from the epidermis. The term is also used to describe the scales of some armored mammals, such as the armadillo and the extinct glyptodon.

Scutes are also often called osteoderms.