Real Dictionary

stickleback
countable noun: A stickleback is a small fish which has sharp points along its back.

stickleback in American English
any of a family (Gasterosteidae, order Gasterosteiformes) of small, bony-plated, marine and freshwater bony fishes with two to eleven sharp spines in front of the dorsal fin: the male builds a nest for the female's eggs
noun: any of the small, pugnacious, spiny-backed fishes of the family Gasterosteidae, inhabiting northern fresh waters and sea inlets, the male of which builds and guards the nest

stickleback in British English
noun: any small teleost fish of the family Gasterosteidae, such as Gasterosteus aculeatus (three-spined stickleback) of rivers and coastal regions and G. pungitius (ten-spined stickleback) confined to rivers. They have a series of spines along the back and occu