also: ひととし · ひととせ
one year; a year
Standard noun for a period of one year. The gloss 'some time ago' reflects a rare, context-dependent use where 一年 can mean 'a year or so ago' in informal speech, but this is not the primary meaning.
One year is 365 days.
He lived in Japan for one year.
This research took a year.
A year passed in the blink of an eye.
I go on a trip twice a year.
I look back on the year at the end of December.
first-year ice