| Singular | Plural | |
|---|---|---|
| Nominativ | circaeom, circaeum, circaeumque | circaea |
| Genitiv | circaei | circaeorum, circaeum, circaeumque |
| Dativ | circaeo | circeis, circaeis |
| Akkusativ | circaeum, circaeumque | circaea |
| Ablativ | circaeo | circeis, circaeis |
| Vokativ | circaeum, circaeumque | circaea |