Source : Webster's Revised Unabridged Dictionary (1913)

Orchidaceous \Or`chi*da"ceous\, a. (Bot.)
   Pertaining to, or resembling, a natural order
   ({Orchidace[ae]}) of endogenous plants of which the genus
   Orchis is the type. They are mostly perennial herbs having
   the stamens and pistils united in a single column, and
   normally three petals and three sepals, all adherent to the
   ovary. The flowers are curiously shaped, often resembling
   insects, the odd or lower petal (called the lip) being unlike
   the others, and sometimes of a strange and unexpected
   appearance. About one hundred species occur in the United
   States, but several thousand in the tropics.

   Note: Over three hundred genera are recognized.