אָב II, , const. אֲבִי, אַב [embracer], father, ancestor, progenitor; teacher; chief, leader; author, originator. Ex. R. s. 46 end המגדל אב the educator is the real father. Lev. R. s. 1 אבי החכמה וכ׳, the father of all wisdom, … the father of prophets. Y. Ned. V, 39ᵇ; a. fr.—אַב בית דין (abbr. אב"ד) president of the Court (Great Sanhedrin), next in dignity to the Nassi. Taan. II, 1; a. fr.—Metaph. origin, cause. Num. R. s. 10 (play on אֲבוֹי, Prov. XXIII, 29) א׳ אוי the cause of woe (sin).—אב מלאכה (for which also עיקר) one of the chief labors forbidden on the Sabbath, opp. תולדה a labor the prohibition of which is based on the ground of its being a species of the former, or derived from the former. Sabb. VII, 1 sq.; a. fr.—[Y. Sabb. II, 5ᵃ, אב שלה, sub. מלאכה.]—אב הטומאה one of the original or direct causes of levitical uncleanness, opp. ולד (child) secondary cause. Toh. I, 5; a. fr.—א׳ הנזק v. Pl.—בנין א׳ creation of a class, i.e. a conclusion, by analogy, from a case explicitly stated in the bibl. law on all similar cases not specified in detail. Sifra introd.—Ib. K’doshim, end, ch. 11 (ref. to Lev. XX, 27) זה ב׳ א׳ לכל דמיהם בם this forms the rule for all cases in which the Bible uses the word d’mēhem bam (that the penalty is stoning to death); a. fr.; v. also בֵּית אב.—Pl. אָבוֹת־, const. אֲבוֹת,
אָב II, fathers, ancestors, patriarchs &c. Ber. 26ᵇ prayers א׳ תקנום have been instituted by the Patriarchs; a. fr.—אבות בתי דינין, v. supra. Ḥag. II, 2.—בת א׳ a woman of noble descent. Num. R. s. 1; a. e.—Metaph. principal, chiefא׳ מלאכות, v. supra. א׳ הטומא׳ Kel. I, 1; v. supra.—א׳ נזיקין (sing. אב הנזק) the chief actionable injuries or damages, from which the subordinate are deduced (תולדות). B. Kam. I, 1; a. e.
אָב II, Aboth, the first section of the Prayer of Benedictions (v. תְּפִלָּה), so called because it alludes to the Patriarchs. R. Hash. IV, 5; a. fr.
אָב II, Aboth, name of a treatise of the Mishnah, containing sayings of Talmudic authorities and belonging to the fourth section, נזיקין, of the Mishnah collection (משניות); also styled פִּרְקֵי א׳ a. מְסֶכֶת א׳. A similar collection of a later date is contained in Talmud Babli editions, named א׳ דרבי נתןAboth d’Rabbi Nathan. [Y. Yoma VIII, 44ᵈ top אב בית נפש v. אֲבֵידָה.]
