Diadem \Di"a*dem\, v. t. To adorn with a diadem; to crown.

Not so, when diadem'd with rays divine. --Pope.

To terminate the evil, To diadem the right. --R. H. Neale.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Diadem \Di"a*dem\, n. [F. diad[`e]me, L. diadema, fr. Gr. ?, fr. ? to bind round; dia` through, across + ? to bind; cf. Skr. d[=a] 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.

2. Regal power; sovereignty; empire; -- considered as symbolized by the crown.

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

Diadem lemur. (Zo["o]l.) See Indri.

Diadem spider (Zo["o]l.), the garden spider.

Source: Webster's Revised Unabridged Dictionary (1913)