| Singular | Plural | |
|---|---|---|
| Nominativ | adelphis | adelphides, adelphidis |
| Genitiv | adelphidis | adelphidum, adelphidium |
| Dativ | adelphidi, adelphide | adelphidibus |
| Akkusativ | adelphidem, adelphidim | adelphideis, adelphides, adelphidis |
| Ablativ | adelphidi, adelphide | adelphidibus |
| Vokativ | adelphis | adelphides |