1. a type of ray (fish) with spines on its back and tail
Usage: marine biology
2. an unmarried woman, especially one considered past the usual age for marriage
Usage: archaic; offensive

Examples

• The fisherman caught a large thornback in his net.
• Thornbacks are commonly found in shallow coastal waters.
• The thornback’s spines help protect it from predators.
• Marine biologists study the migration patterns of thornback rays.
• The aquarium has a tank dedicated to thornbacks and other rays.