Edition of 1920. See also Ab (Semitic) on Wikipedia, and the disclaimer.

ABBA (same as papa, etc.), Aramaic form of Hebrew for “father.” In the New Testament, used as an address to God; in the Talmud, a scholar's title of honor; also used as part of proper names; and at present the title of Syriac, Coptic, and Ethiopic bishops. See Pope.