A fleur-de-lis is a symbol that's commonly used as a decoration on flags, coats of arms, and even on buildings. The fleur-de-lis is based on the shape of a lily.
In French, fleur-de-lis means "lily flower" or "flower of the iris." It's been used for centuries to represent a vast variety of things, including royalty, French cultural heritage, Christianity, light, defense, and female virtue. Its closest association is probably the French monarchy and its coats of arms — the fleur-de-lis has gone on to appear on flags, in college and sports team logos, and in many religious works of art.