di·a·dem
n.
1. A crown worn as a sign of royalty.
2. Royal
power or dignity.
tr.v. di·a·demed, di·a·dem·ing, di·a·dems
Middle English diademe, from Old
French, from
Latin diadma, from Greek, band, from diadein, to bind around : dia-, dia- + dein, d-, to bind.