(adjective) : Rēgillus, i, m.
* A town of the Sabines, whence Appius Claudius emigrated to Rome, Liv. 2, 16 Drak.; also called Rēgilli, ōrum, m., Suet. Tib. 1.— Hence, Rēgillānus, a, um, and Rēgillensis, e, , of or belonging to Regillus: Claudius Appius Regillanus,Suet. Tib. 2: Claudius Regillensis,Liv. 8, 15.
* A small lake in Latium (the mod. Cornufelle), celebrated for the victory over the Latins gained there by the Romans under the dictator Postumius, Cic. N. D. 3, 5, 11; called also lacus Regillus,Liv. 2, 19; Plin. 33, 2, 11, § 38; and Regilli lacus,Flor. 1, 11, 2; Aur. Vict. Vir. Ill. 16.— Hence, Rēgillensis, surname of the Postumii: M. Postumio Regillensi,Liv. 4, 49, 7: A. et L. Postumii Regillenses,id. 6, 22, 5.
* A Roman surname in the Aemilian gens, Cic. Att. 12, 24, 2: M. Aemilius Regillus,Liv. 24, 7 fin.; 8; 29, 11 fin.; 38.

Male Personal name
Confirmed occurences in the Roman Empire:

• Ti. Claudius M. Appius Atilius Bradua Regillus Atticus (Masc, senator), ref: PIR C 0785 | PIR ID4178
• Ti. Claudius Herodes L. Vibullius Regillus (Masc, senator), ref: PIR C 0886 | PIR ID4315
• C. Etrilius Regillus L. Laberius Priscus (Masc, senator), ref: PIR E 0104 | PIR ID5618
• Paullus Aemilius Regillus (Masc, senator), ref: PIR A 0396 | PIR ID10170
• Regillus (Masc, eques), ref: PIR R 0037 | PIR ID11371