| Singular | Plural | |
|---|---|---|
| Nominativ | diadema, diadema | diademata, diademae |
| Genitiv | diademae, diademai, diadematis | diademarum, diademum, diadematium, diadematum |
| Dativ | diademate, diademati, diademae, diademai | diademis, diademabus, diadematibus |
| Akkusativ | diadema, diademam | diademas, diademata |
| Ablativ | diadema, diademad, diademate | diademis, diademabus, diadematibus |
| Vokativ | diadema, diadema | diademata, diademae |