Originally: (of a polyp) having the form or structure of a sea anemone. Later (more widely): having a radiated form; having rays diverging from a centre.
Origin
Early 19th century. From actinia or its etymon ancient Greek ἀκτῖν-, ἀκτίς ray + -iform.
Definition of actiniform in US English:
actiniform
adjectiveakˈtɪnɪfɔːm
Originally: (of a polyp) having the form or structure of a sea anemone. Later (more widely): having a radiated form; having rays diverging from a centre.
Origin
Early 19th century. From actinia or its etymon ancient Greek ἀκτῖν-, ἀκτίς ray + -iform.