Webster's Revised Unabridged Dictionary · 1913

Elytron

Elytron (?; 277) , noun

[New Latin, from Greek 'e`lytron, from 'ely`ein to roll round.]

(a)
(Zoology) One of the anterior pair of wings in the Coleoptera and some other insects, when they are thick and serve only as a protection for the posterior pair.
(b)
(Zoology) One of the shieldlike dorsal scales of certain annelids. See Chatopoda.

Also: Elytrum