What does starfish mean?
A starfish is a marine animal named for its usually star-shaped body, with arms radiating from a central disc. Most have five arms, although some species have more, and many can regenerate lost arms. Starfish live on the sea bed and feed on animals such as mussels, clams, and other invertebrates. The name is somewhat misleading because they are not fish: they are echinoderms, a group that also includes sea urchins, sea cucumbers, and brittle stars. Starfish are found in oceans worldwide, from warm tropical reefs to cold polar waters. The common plural is starfish, although starfishes is also accepted. In scientific writing, sea star is often preferred to emphasize the animal’s true biological classification.
nounA marine animal with a star-shaped body and typically five or more arms, commonly living on the sea bed. Despite its name, it is not a fish but an echinoderm related to sea urchins and brittle stars.
- A star-shaped marine animal with typically five or more arms, belonging to the echinoderms and commonly found on the sea bed.
"A bright orange starfish was clinging to the rock beneath the shallow water."
"Marine biologists observed a large colony of starfish in the tidal pool."
"The aquarium displayed several unusual starfish species from cold-water oceans."
Starfish is the usual plural form and is widely used in both general and scientific writing. Starfishes is grammatically standard but less common.
"Researchers counted hundreds of starfish along the rocky coast."
A starfish is named for its shape, but it is not a fish: it belongs to a family of marine animals called echinoderms.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does starfish come from?
The word is an English compound formed from star and fish, both of which are ancient Germanic words: star comes from Old English steorra, while fish comes from Old English fisc. The compound reflects the animal’s radiating, star-like shape. Later English formed related terms from the same broad idea of a star, including stellar, astral, and asterisk, the last originally referring to a small star used as a mark.
Related word forms
How starfish is actually used
The singular and plural are both commonly written starfish. Starfishes is also standard but is used less often. The alternative term sea star is preferred in some scientific contexts because starfish are not fish.