fleur-de-lis or fleur-de-lys 
(flûr′də-lē, flr′-)
(flûr′də-lē, flr′-)n. pl. fleurs-de-lis or fleurs-de-lys (flûr′də-lēz, flr′-)
1. An iris.
2.
a. Heraldry A device consisting of a stylized three-petaled iris flower, used as the armorial emblem of the kings of France.
b. A similar design used as a decorative motif.
[Middle English flour de lice, from Old French flor de lis : flor, flower + de, of + lis, lily.]
fleur-de-lissterling silver brooch by Francisco Rebajes
(1905?-1990)