Source : Webster's Revised Unabridged Dictionary (1913)

Bijou \Bi*jou"\, n.; pl. {Bijoux}. [F.; of uncertain origin.]
   A trinket; a jewel; -- a word applied to anything small and
   of elegant workmanship.

Source : WordNet®

bijou
     n : a small and delicately worked piece
     [also: {bijoux} (pl)]