v. t. To place or set in a diadem, as a gem or gems. [ 1913 Webster ]

n. [ F. diadème, L. diadema, fr. Gr. &unr_;, fr. &unr_; to bind round; dia` through, across + &unr_; to bind; cf. Skr. dā to bind. ] 1. Originally, an ornamental head band or fillet, worn by Eastern monarchs as a badge of royalty; hence (later), also, a crown, in general. “The regal diadem.” Milton. [ 1913 Webster ]

2. Regal power; sovereignty; empire; -- considered as symbolized by the crown. [ 1913 Webster ]

3. (Her.) An arch rising from the rim of a crown (rarely also of a coronet), and uniting with others over its center. [ 1913 Webster ]

Diadem lemur. (Zool.) See Indri. --
Diadem spider (Zool.), the garden spider. [ 1913 Webster ]

v. t. To adorn with a diadem; to crown. [ 1913 Webster ]

Not so, when diadem'd with rays divine. Pope. [ 1913 Webster ]

To terminate the evil,
To diadem the right. R. H. Neale. [ 1913 Webster ]