Source : Webster's Revised Unabridged Dictionary (1913)

Piperaceous \Pip`er*a"ceous\, a. [L. piper pepper.] (Bot.)
   Of or pertaining to the order of plants ({Piperace[ae]}) of
   which the pepper ({Piper nigrum}) is the type. There are
   about a dozen genera and a thousand species, mostly tropical
   plants with pungent and aromatic qualities.