אֲרוּבָּה f. (b. h. אֲרֻבָּה, ארב) opening, whence 1) an aperture in the roof looking to the ground floor (answering to the Greek hypaithron, Roman compluvium), contrad. fr. חַלֹּון a garret window in the wall projecting above the flat roof. Bets. V, 1 (35ᵇ); cmp. Rashi a. l. Nidd. 20ᵇ כסומא בא׳ like a blind man finding his way down from the ărubbah, i.e. hitting the truth by chance. Ohol. X, 1; a. fr.—Pl. אֲרוּבֹּות. Ib. 4 sq.; a. e. —2) the opening panel of folding doors. —Pl. as supra. Yoma 76ᵃ. [Sabb. 43ᵃ; 153ᵇ; Kel. XV, 2 read with Ar. אֲרוּכוֹת.]