Definition from Wiktionary, the free dictionary
turtleback (plural turtlebacks)
- Anything having the shape of a turtle's back (that is, its shell.)
- (The addition of quotations indicative of this usage is being sought): A library binding of a mass market paperback with a generic hardcover.
- Any plant of the genus Psathyrotes of annual and perennial forbs and low subshrubs native to dry areas of southwestern North America.