Perhaps via Estonian Iirimaa. Morphologically from īrõ + mō.
Īrõmō
| singular (ikšlug) | plural (pǟgiņlug) | |
|---|---|---|
| nominative (nominatīv) | Īrõmō | – |
| genitive (genitīv) | Īrõmō | – |
| partitive (partitīv) | Īrõmōdõ | – |
| dative (datīv) | Īrõmōn | – |
| instrumental (instrumentāl) | Īrõmōkõks | – |
| illative (illatīv) | Īrõmōzõ | – |
| inessive (inesīv) | Īrõmōs Īrõmōsõ |
– |
| elative (elatīv) | Īrõmōst Īrõmōstõ |
– |
| allative (allatīv) | Īrõmōlõ | – |
| adessive (adesīv) | Īrõmōl | – |
| ablative (ablatīv) | Īrõmōld | – |