בֹּוסֶר, half-ripe fruit, esp. grapes. Shebi. IV, 8 הב׳ משהביא וכ׳ the boser from the time it contains liquid. Gitt. III, 8 (31ᵃ) בשעת כניסת המים בב׳ when the liquid is beginning to gather in the boser; (oth. opin. when it can be put in water for making vinegar; v. Rashi a. l.). Pes. 53ᵃ הוא ב׳ וכ׳ boser indicates the same stage of ripening as gerua, v. גָּרַע Hif. Y. Maasr. I, 49ᵃ top; Succ. 36ᵃ אתרוג הב׳ a half-ripe Ethrog. Y. B. Kam. VI, 5ᵇ bot.; a. fr.