Emily Dickinson Lexicon

diadem (-s), n. [Fr. < Gk. διάδημα, regal fillet of Persian kings.] (webplay: crown, ends, forehead, gold, head, kings, let, made, neck, ornament, pearls, plain, power, set, sometimes, stones, supreme, worn).

1. Crown; headband worn by kings as a badge of royalty; fillet often adorned by jewels; (see Isaiah 28:5).
2. Distinguished decoration; principal ornament; cincture conferring glory or dignity; (see Job 29:14).