The Collaborative International Dictionary of English v.0.48:

Bijou \Bi*jou"\, n.; pl. Bijoux. [F.; of uncertain origin.]
   A trinket; a jewel; -- a word applied to anything small and
   of elegant workmanship.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bijou
    n 1: a small and delicately worked piece

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "bijou":
   anklet, armlet, bangle, beads, bracelet, breastpin, brooch, chain,
   chaplet, charm, chatelaine, circle, coronet, crown, diadem,
   earring, fob, gem, jewel, locket, necklace, nose ring, pin,
   precious stone, rhinestone, ring, stickpin, stone, tiara, torque,
   wampum, wristband, wristlet