Source : Webster's Revised Unabridged Dictionary (1913)

Alcyonium \Al`cy*o"ni*um\, n. [Gr. ? a zo["o]phyte, so called
   from being like the halcyon's nest.] (Zo["o]l.)
   A genus of fleshy Alcyonaria, its polyps somewhat resembling
   flowers with eight fringed rays. The term was also formerly
   used for certain species of sponges.