kertaalleen

Kertaalleen is a Finnish adverb meaning “on one occasion” or “one time only.” It is used to indicate that an action, event, or condition occurs or is applicable a single time, rather than repeatedly. The term is typically found in formal, administrative, legal, or technical language, and is less common in casual speech.

Etymology and form: The word is a compound of kerta, meaning an instance or occasion, and alleen, a directional element that in this context conveys limitation to a single occurrence. Kertaalleen is usually written as one word and functions as an adverb that modifies a verb or entire clause.

Usage and nuance: Kertaalleen often appears in procedural or rule-based texts to restrict frequency. For example, it can appear in instructions or legal provisions to specify that a measure must be carried out only once. In everyday Finnish, expressions like vain kerran or yksi kerta may be used instead, but kertaalleen carries a more formal or administrative tone. The term can also appear in descriptive writing to underscore that an event happened a single time.

Related terms and contrast: Kertaalleen contrasts with phrases such as kerta toisensa jälkeen (“time after time”) and useammissa kertatilanteissa (“in multiple instances”). It shares the semantic field of frequency and occurrence with other kerta- compounds but maintains a distinctly one-off emphasis.

See also: kerta, kerran, ainakaan ikinä.