'Thornback' definitions:

Definition of 'Thornback'

From: GCIDE

Thornback \Thorn"back`\, n.
1. (Zool.) A European skate (Raia clavata) having thornlike spines on its back. [1913 Webster]
2. (Zool.) The large European spider crab or king crab ({Maia squinado}). [1913 Webster]