King James Bible Dictionary

The tiara of a king (Ezekiel 21:26; Isaiah 28:5; 62:3); the turban (Job 29:14). In the New Testament a careful distinction is drawn between the diadem as a badge of royalty (Revelation 12:3; 13:1; 19:12) and the crown as a mark of distinction in private life. It is not known what the ancient Jewish "diadem" was. It was the mark of Oriental sovereigns. (See CROWN.)

Ezekiel 21:26

What the "diadem" of the Jews was we know not. That of other nations of antiquity was a fillet of silk, two inches broad, bound round the head and tied behind. Its invention is attributed to Liber. Its color was generally white, sometimes, however, it was of blue, like that of Darius; and it was sown with pearls or other gems, (Zechariah 9:16) and enriched with gold. (Revelation 9:7) It was peculiarly the mark of Oriental sovereigns. In (Esther 1:11; 2:17) we have cether for the turban worn by the Persian king, queen or other eminent persons to whom it was conceded as a special favor. The diadem of the king differed from that of others in having an erect triangular peak. The words in (Ezekiel 23:15) mean long and flowing turbans of gorgeous colors. [CROWN]

DIADEM, noun [Gr., to gird; to bind. Latin ]

1. Anciently, a head-band or fillet worn by kings as a badge or royalty. It was made of silk, linen or wool, and tied round the temples and forehead, the ends being tied behind and let fall on the neck. It was usually white and plain; sometimes embroidered with gold, or set with pearls and precious stones.

2. In modern usage, the mark or badge of royalty, worn on the head; a crown; and figuratively, empire; supreme power.

3. A distinguished or principal ornament.

A diadem of beauty. Isaiah 28:5.

DIADEMED, adjective Adorned with a diadem; crowned; ornamented.