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 (kū́rios, “lord”) is not a derivative; rather, κῦρος (kûros) is a back-formation from the former.
κῦρος • (kûros) n (genitive κῡ́ρεος); third declension
| Case / # | Singular | Dual | Plural | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nominative | τὸ κῦρος tò kûros |
τὼ κῡ́ρεε tṑ kū́ree |
τᾰ̀ κῡ́ρεᾰ tà kū́rea | ||||||||||
| Genitive | τοῦ κῡ́ρεος toû kū́reos |
τοῖν κῡρέοιν toîn kūréoin |
τῶν κῡρέων tôn kūréōn | ||||||||||
| Dative | τῷ κῡ́ρεῐ̈ tôi kū́reï |
τοῖν κῡρέοιν toîn kūréoin |
τοῖς κῡ́ρεσῐ / κῡ́ρεσῐν toîs kū́resi(n) | ||||||||||
| Accusative | τὸ κῦρος tò kûros |
τὼ κῡ́ρεε tṑ kū́ree |
τᾰ̀ κῡ́ρεᾰ tà kū́rea | ||||||||||
| Vocative | κῦρος kûros |
κῡ́ρεε kū́ree |
κῡ́ρεᾰ kū́rea | ||||||||||
| Notes: |
| ||||||||||||