Source : Webster's Revised Unabridged Dictionary (1913)

La valliere \La val`liere"\, or Lavalliere \La`val`liere"\, n.
   A neck ornament consisting of a chain and single pendant, or
   drop.

Source : WordNet®

lavalliere
     n : jewelled pendant worn on a chain around the neck [syn: {lavaliere},
          {lavalier}]