eräänä

Eräänä is a Finnish adverb used to mark a moment in the past, most often as part of a narrative opening. It signals that the speaker is recounting an event that took place at some unspecified time, giving a sense of immediacy to the story.

In practice, eräänä is most commonly found in the fixed expression eräänä päivänä, meaning “one day.” It can also be paired with other time words such as iltana or yönä to indicate different parts of the day, for example eräänä iltana or eräänä yönä. The phrase is typical in storytelling, anecdotes, folklore, and reminiscences, and it is less common in formal or factual writing.

Grammatically, eräänä functions as a temporal adverb that requires a following time noun to complete its meaning in most sentences. A typical sentence would start with eräänä (päivänä/iltana/yönä) and continue with a description of what happened. For example: Eräänä päivänä kaupungissa tapahtui jotain kummallista. Translation: One day, something strange happened in the city. Another example: Eräänä yönä he kuulivat outoa ääntä. Translation: One night they heard a strange noise.

Notes on style and nuance: the expression tends to convey a sense of storytelling, recollection, or fairy-tale atmosphere. It is widely understood by Finnish speakers and is a common opening in informal and literary narration. It should not be confused with other uses of the stem erä, which can have different meanings in unrelated contexts.