Asteroidea

Part of speech: noun

Definitions

1. A class of marine animals that includes starfish and sea stars, characterized by a central disk and radiating arms that help them to move and feed
2. A phylum of echinoderms distinguished by their star-like shape and ability to regenerate lost limbs, playing important roles in marine ecosystems
3. An aquatic group of organisms known for their pentamerous symmetry and diverse habitats, often noted for their unique feeding mechanisms and ecological significance

Etymology: Asteroidea is the scientific name for the class of echinoderms we call starfish, and its history is a straightforward piece of Greek compounding. It combines "astēr", "star", with "eidos", "form" or "shape", and the Greek suffix "-oidea" meaning "resembling" or "of the form of". Put together, it means "star-like" or "star-shaped", which describes the animals' body plan well. The name was coined in the scientific Latin of the early modern period, when zoologists were naming groups of animals with Greek and Latin roots. It is a technical coinage rather than a word that circulated among ancient Greeks, who had their own words for these creatures. Its use in English is therefore confined largely to biology.

Synonyms: starfish, sea star