κῦρος

See also: κύρος and Κῦρος

Ancient Greek

From Proto-Hellenic *kūrós, from Proto-Indo-European *ḱuh₁-ró-s, from *ḱewh₁- (“to swell, be strong”),^[1] the same root of κυέω (kuéō, “to be pregnant”), κῦμα (kûma, “wave”), Sanskrit शवस् (śavas, “strength, power”) and Irish curadh (“hero”).

κῡ́ρῐος (kū́rĭos, “lord”) is not a derivative; rather, κῦρος (kûros) is a back-formation from the former.

κῦρος • (kûros) n (genitive κῡ́ρεος); third declension

Third declension of τὸ κῦρος; τοῦ κῡ́ρεος (Attic)

Case / #	Singular	Dual	Plural
Nominative	τὸ κῦρος tò kûros	τὼ κῡ́ρεε tṑ kū́ree	τᾰ̀ κῡ́ρεᾰ tằ kū́reă
Genitive	τοῦ κῡ́ρεος toû kū́reos	τοῖν κῡρέοιν toîn kūréoin	τῶν κῡρέων tôn kūréōn
Dative	τῷ κῡ́ρεῐ̈ tōî kū́reĭ̈	τοῖν κῡρέοιν toîn kūréoin	τοῖς κῡ́ρεσῐ / κῡ́ρεσῐν toîs kū́resĭ(n)
Accusative	τὸ κῦρος tò kûros	τὼ κῡ́ρεε tṑ kū́ree	τᾰ̀ κῡ́ρεᾰ tằ kū́reă
Vocative	κῦρος kûros	κῡ́ρεε kū́ree	κῡ́ρεᾰ kū́reă
Notes:	This table gives Attic inflectional endings. For declension in other dialects, see Appendix:Ancient Greek dialectal declension.

^ Beekes, Robert S. P. (2010) “κύριος”, in Etymological Dictionary of Greek (Leiden Indo-European Etymological Dictionary Series; 10), with the assistance of Lucien van Beek, Leiden, Boston: Brill, →ISBN, pages 806-7