noun Any animal with a thorny back, especially marine animals, such as: The thornback guitarfish (Platyrhinoidis triseriata), a species of ray in the north-eastern Pacific Ocean. The thornback ray or thornback skate (Raja clavata), a species of ray in the Atlantic Ocean. The thornback skate (Dentiraja lemprieri), a fish endemic to Australia.
noun The thornback guitarfish (Platyrhinoidis triseriata), a species of ray in the north-eastern Pacific Ocean.
noun The thornback ray or thornback skate (Raja clavata), a species of ray in the Atlantic Ocean.
noun The thornback skate (Dentiraja lemprieri), a fish endemic to Australia.
noun A woman over a certain age (variously 26 or 30) who has never married, older than a spinster.