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† dĭădēma, ătis, n. (diadēma, ae, f., Pompon. ap. Prisc. p. 679 P. [Com. v. 163 Rib.]; Ap. M. 10, p. 253, 10), = διάδημα, a royal head-dress, a diadem (for syn. cf.: infula, vitta, redimiculum), Cic. Phil. 2, 34, 85; 3, 5, 12; Quint. 9, 3, 61; Suet. Caes. 79; Hor. C. 2, 2, 21; Juv. 8, 259; Vulg. Apoc. 12, 3 al.
dĭădēmātus, a, um, adj. [diadema], adorned with a diadem: Apollo, Plin. 34, 8, 19, § 79.
Hence,
Dĭădēmātus, i, m., a Roman surname, Cic. Post. Red. ad Quir. 3, 6.