Source : Webster's Revised Unabridged Dictionary (1913)

Alcyonacea \Al`cy*o*na"ce*a\, n. pl. [NL.] (Zo["o]l.)
   A group of soft-bodied Alcyonaria, of which {Alcyonium} is
   the type. See Illust. under {Alcyonaria}.

Source : WordNet®

Alcyonacea
     n : comprising the soft corals [syn: {suborder Alcyonacea}]