Definition of alcyonarian
: any of a subclass (Alcyonaria) of colonial anthozoans (such as the sea pens) having polyps with eight branched tentacles and eight septa
Origin and Etymology of alcyonarian
ultimately from Greek alkyoneion, a zoophyte, from neuter of alkyoneios of a kingfisher, from alkyon kingfisher; from its resemblance to a kingfisher's nest
First Known Use: 1861
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