unripe plum; green plum
Refers specifically to the unripe, green fruit of the Japanese plum (ume), often used for making umeboshi or plum wine.
青梅で梅酒を作るのが楽しみです。
I look forward to making plum wine with unripe plums.
この時期、スーパーで青梅が売られています。
At this time of year, unripe plums are sold at the supermarket.
I pickled green plums in salt to make umeboshi.
Making plum wine from green plums is a summer pleasure.