The Collaborative International Dictionary of English v.0.48:

Herodiones \He*ro`di*o"nes\ (h[-e]*r[=o]`d[i^]*[=o]"n[=e]z), n.
   pl. [NL., fr. Gr. 'erwdio`s a heron.] (Zool.)
   A division of wading birds, including the herons, storks, and
   allied forms. Called also Herodii. -- He*ro`di*o"nine, a.
   [1913 Webster]