Unknown. Probably from the towns of Karkku and Mouhijärvi; earlier attestation potentially Per Örri (1546, Mouhijärvi), which may hint at the surname being a variant of Örri (< öristä?); the earlier attestation with an initial i- is from the 1600s. Compare Irjala, or alternatively iristä.
Irri
| Inflection of Irri (Kotus type 5/risti, no gradation) | |||
|---|---|---|---|
| nominative | Irri | Irrit | |
| genitive | Irrin | Irrien | |
| partitive | Irriä | Irrejä | |
| illative | Irriin | Irreihin | |
| singular | plural | ||
| nominative | Irri | Irrit | |
| accusative | nom. | Irri | Irrit |
| gen. | Irrin | ||
| genitive | Irrin | Irrien | |
| partitive | Irriä | Irrejä | |
| inessive | Irrissä | Irreissä | |
| elative | Irristä | Irreistä | |
| illative | Irriin | Irreihin | |
| adessive | Irrillä | Irreillä | |
| ablative | Irriltä | Irreiltä | |
| allative | Irrille | Irreille | |
| essive | Irrinä | Irreinä | |
| translative | Irriksi | Irreiksi | |
| abessive | Irrittä | Irreittä | |
| instructive | — | Irrein | |
| comitative | See the possessive forms below. | ||