| Nominative | sinus |
| Genitive | sinusu; sinu |
| Dative | sinusu; sinu |
| Accusative | sinus |
| Vocative | sinuse; sine |
| Locative | sinusu; sinuse; sinu |
| Instrumental | sinusem; sinem |
| Nominative | sinusy; siny |
| Genitive | sinusů; sinů |
| Dative | sinusům; sinům |
| Accusative | sinusy; siny |
| Vocative | sinusy; siny |
| Locative | sinusech; sinech |
| Instrumental | sinusy; siny |