עָצַר (b. h.; cmp. אָצַר) [to press,] to close up; to detain; to ward off; to gather, store away. Succ. 38ᵃ עוֹצֶרֶת רוחות וכ׳ wards off evil winds and dews (v. infra). Num. R. s. 19 היאך יכול … וַעֲצָרוֹ how could the angel of death strike a man that had stood up against the angel of death and warded him off? (ref. to Num. XVII, 13). Sifré Num. 151; Yalk. ib. 782 (ref. to עצרת, Num. XXIX, 35) עֲצָרוֹ הכתוב מלצאת the Scripture keeps him (the pilgrim) from leaving (Jerusalem, on the eighth day). Pesik. R. (ed. Fr.) addit. s. 4; Pesik. Bayom, p. 193ᵇ הק"בה עוֹצֵר וכ׳ the Lord locks his Presence up with them, v. infra. Ab. Zar. 71ᵃ עול תחתי לעוֹצֵר, v. עָלַל; a. fr.—Part. pass. עָצוּר; f. עֲצוּרָה; pl. עֲצוּרִים, עְצוּרִין; עְצוּרוֹת. Sifré l. c. מה זה ע׳ מלצאת אף זה ע׳ וכ׳ as on this (the eighth day) one is prohibited to leave, so is one on this (the first day). Sifré Deut. 135 (ref. to עצרת, Deut. XVI, 8) יכול יהא אדם ע׳ כל וכ׳ from this you might infer that one must be confined the whole day in the schoolhouse (for religious exercises). Ib. מה שביעי ע׳ אף ששי ע׳ as the seventh day is under restrictions (as to week-day labor), so is the sixth day (i.e. the days intervening between the first and the seventh day); אי מה שביעי ע׳ מכל מלאכה וכ׳ you might infer from this that as the seventh day is under restriction as regards all sorts of labor (even work of necessity), so is the sixth; Ḥag. 18ᵃ השביעי ע׳ בכל מלאכה … ימים ע׳ וכ׳ the seventh day is under a general restriction, but the six days are not; Yalk. Deut. 904; ib. 907. Ḥull. 67ᵃ בורות … שהן ע׳ ככלים wells, pits and caves, the waters of which are restrained as in vessels; Yalk. Lev. 537 עצירים … בכלים (corr. acc.); a. fr.
Nif. - נֶעֱצָר to be detained; to be gathered together. Pesik. R. l. c. כל זמן שישראל נֶעֱצָרִין וכ׳ as long as Israel holds festive gatherings in synagogues and schoolhouses, the Lord locks up &c. (v. supra); Pesik. l. c.ᵃ מְעַצְּרִין (Pi.). Yalk. Num. 782 (ref. to עצרת, v. supra) למה נֶעֶצְרוּ עיד יום אחד why are they detained one more day? Taan. 7ᵇ הגשמים נעצרין the rains are withheld. Ib. 8ᵃ השמים נעצרין מלהוריד וכ׳ the heavens are locked up so as not to let down rain &c.; a. fr.