inessiiviseen

In Finnish grammar, the inessive (inessiivinen) is a locative case that marks being inside or within something. It answers questions about location such as "Where is X?" and is typically used with nouns to express interior confinement or containment.

The inessive forms are built with the endings -ssa or -ssä for singular and -issa or -issä for plural, chosen according to vowel harmony. The basic pattern is -ssa/-ssä in the singular and -issa/-issä in the plural. Examples: talo in the singular becomes talossa (in the house); kirja becomes kirjassa (in the book). Plural forms include taloissa (in the houses) and kirjoissa (in the books). Other common examples: pöytä (table) → pöydässä (in the table); kissa (cat) → kissoissa (in the cats).

Usage notes:

- The inessive typically expresses a static location, contrasting with elative (from inside), which uses -sta/-stä; and adessive (on, at) or allative (onto) forms, which use their respective endings.

- It often follows verbs of existence or location, such as asua (to live) or olla (to be): Asun talossa. (I live in the house.)

- Adjectives and possessive forms agree in the same case when the noun is declined, so you can say vanhassa talossa (in the old house) or minun talossani (in my house).

See also: other Finnish cases and their typical functions, including elative, adessive, allative, and illative, which handle movement, location, and direction in different ways.