נִדָּה, (v. נִידּוּי) isolation, condition of uncleanness, esp. period of menstruation. Sabb. 64ᵇ, a. e. (ref. to Lev. XV, 33) בנִדָּתָהּ ההא וכ׳ she shall remain in her isolation (from her husband) until &c. Ib. VI, 5 שהתקינה לנדתה which she has prepared for her menstruating time. Ib. II, 6 בנ׳ (= במצות נ׳) in the observance of the laws connected with menstruation; a. fr.
נִדָּה, (sub. בעלת) a woman during menstruation, menstruant. Nidd. I, 7 חוץ מן הנ׳, expl. ib. 11ᵃ בתוך ימי נדתה during the days of actual menstruation. Treat. Kallah beg. נ׳ שלא טבלה a woman after menstruation before she has taken the ritual bath; כנ׳ is to be treated like a woman during menstruation; a. fr.—Pl. נִדּוֹת. Nidd. IV, 1 נ׳ are to be treated like menstruants; a. fr.—Niddah, name of a treatise, of the Order of Tohăroth, of Mishnah, Tosefta and Talmud Babli and Y’rushalmi (fragmentary).—Ab. III, 18 פתחי נדה the laws treated in Arakh. II, 1 (8ᵃ), v. פֶּתַח.