French for "flower of the lily", this is a common symbol used in medieval heraldry, but is most notable with France, because of their common use of gold fleur-de-lis on royal blue backgrounds. It was used on their flags, coats of arms, and royal robes
(as in the picture, although Napoleon swapped that for gold eagles on a vermilion background).
It's still used in Spain and Luxemburg due to their royalty being part of the Burbon line.
In modern fiction, it's often a motif to refer to the grander styles of old.
- The call girl service in L.A. Confidential was called this (I would have liked to use the matchbook for the picture, but I couldn't find one).