one evening; some evenings
Used as a noun or adverb to refer to a single evening or occasionally to several evenings. Often appears in literary or slightly formal contexts.
One evening, he suddenly came to visit.
I can't forget our conversation that one evening.
short story; short-story writer
Compound of 一 (one) and 夕 (evening). The reading いっせき follows regular sound changes for 一 before an unvoiced consonant.