A starfish is a flat, star-shaped creature with five arms that lives in the sea.
starfish in British English
(ˈstɑːˌfɪʃ)
nounWord forms: plural-fish or -fishes
any echinoderm of the class Asteroidea, such as Asterias rubens, typically having a flattened body covered with a flexible test and five arms radiating from a central disc
starfish in American English
(ˈstɑrˌfɪʃ)
nounWord forms: pluralˈstarˌfish or ˈstarˌfishes
any of a subclass (Asteroidea) of echinoderms with a hard, spiny skeleton and five or more arms or rays arranged like the points of a star; asteroid