ETYM French diadčme, Latin diadema, from Greek, to bind round.
1. Originally, an ornamental head band or fillet, worn by Eastern monarchs as a badge of royalty; hence (later), also, a crown, in general.
2. Regal power; sovereignty; empire; -- considered as symbolized by the crown.
3. An arch rising from the rim of a crown (rarely also of a coronet), and uniting with others over its center.
Crown; fillet.