Source : Webster's Revised Unabridged Dictionary (1913)

Petaloideous \Pet`al*oid"e*ous\, a. (Bot.)
   Having the whole or part of the perianth petaline.

   {Petaloideous division}, that division of endogenous plants
      in which the perianth is wholly or partly petaline,
      embracing the {Liliace[ae]}, {Orchidace[ae]},
      {Amaryllide[ae]}, etc.

Source : WordNet®

Orchidaceae
     n : enormous cosmopolitan family of perennial terrestrial or
         epiphytic plants with fleshy tubers or rootstocks and
         unusual flowers [syn: {family Orchidaceae}, {orchid
         family}]