出典:Wiktionary
From the plural of Old Latin *grātis, from Proto-Italic *grātis, from Proto-Indo-European *gʷérHtis, from the root *gʷerH- (“to welcome, greet, praise”) + *-tis (deverbal abstract noun–forming suffix). Cognates include Oscan (brateís), Paelignian brat, brais, Vestinian brat, Old Church Slavonic жрьти (žrĭti, “to offer, sacrifice”) and Sanskrit गूर्ति (gūrtí, “approval, praise, welcoming; benediction”). Compare grātia.
This noun originally appeared only in the nominative and accusative plural (The genitive, dative, かつ vocative 複数形 are unattested かつ ablative 複数形 only rarely) and was used with agō when rendering thanks to the gods. grātiās agō was generally used for thanks between humans.
Third-declension noun (i-stem), plural only.
| Case | Plural |
|---|---|
| Nominative | grātēs |
| Genitive | grātium |
| Dative | grātibus |
| Accusative | grātēs grātīs |
| Ablative | grātibus |
| Vocative | grātēs |