what is a diadem
1. (Jewellery) a royal crown, esp a light jewelled circlet. 2. royal dignity or power. vb. (Jewellery) (tr) to adorn or crown with or as with a diadem. [C13: from Latin diadÄma, from Greek: fillet, royal headdress, from diadein to bind around, from dia- + dein to bind]