Definition of octactinian in English:

octactinian

Pronunciation /ɒktakˈtɪnɪən/

noun

rare Zoology
  • An anthozoan coral of the subclass Octocoralliae (formerly called Octactinia) whose polyps bear eight pinnate tentacles.

Origin

Late 19th century; earliest use found in George Rolleston (1829–1881), physician and physiologist. From scientific Latin Octactiniae, former subclass name (C. G. Ehrenberg Die Corallenthiere des Rothen Meeres 53; from ancient Greek ὀκτα- + ἄκτιν-, ἀκτίς ray + scientific Latin -iae, plural of -ia) + -an.