What does actinaria mean?
The definition of actinaria
Ac`ti*na”ri*a, n. pl.
Etym: [NL., from Gr. (Zoöl.)

A large division of Anthozoa, including those which have simple tentacles and do not form stony corals. Sometimes, in a wider sense, applied to all the Anthozoa, expert the Alcyonaria, whether forming corals or not.