Koulun

Koulun is the genitive singular form of the Finnish noun koulu, meaning "school." It functions as a possessive or associative modifier in noun phrases. In Finnish, possession is marked by the genitive, which typically precedes the noun it modifies, while the head noun appears in its own case. For example, koulun piha means "the school’s yard" or "the yard of the school," and koulun ovi means "the school’s door."

The genitive form is also used to express origin, association, or relevance to the noun that follows. Common usages include describing location or ownership, as in koulun kautta ("via the school"), koulun johto ("the school’s leadership"), and koulun opettajat ("the school’s teachers"). In plural contexts, the head noun can be in its plural form, for instance koulun opettajat (the school’s teachers), with koulun still in genitive singular to modify the plural head noun.

Etymology and grammar: koulun is formed by attaching the genitive suffix -n to koulu. This pattern is a core feature of Finnish possessive grammar, where the genitive marks the possessor and the head noun carries its own case. The genitive construction is widely used across everyday Finnish to express relationships such as ownership, affiliation, and origin.

See also: koulu (the school). The genitive case system is a foundational aspect of Finnish grammar and extends beyond koulun to many other nouns to indicate similar relationships.