Source : Webster's Revised Unabridged Dictionary (1913)

Bidet \Bi*det"\, n. [F. bidet, perh. fr. Celtic; cr. Gael.
   bideach very little, diminutive, bidein a diminutive animal,
   W. bidan a weakly or sorry wretch.]
   1. A small horse formerly allowed to each trooper or dragoon
      for carrying his baggage. --B. Jonson.

   2. A kind of bath tub for sitting baths; a sitz bath.

Source : WordNet®

bidet
     n : a basin for washing genitals and anal area