ab

AB, A-B, Ab, or ab can each refer to several things.
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ab- (also abs- before certain consonants) is a particle, most often a prefix, that occurs in many languages. In Latin it was both a prefix and a preposition meaning "off, away (from), departing from, outside of" and expressed the idea of removal, absence, separation, or a lower value. It first appeared in English in the Middle English period in words borrowed from Old French, and continued to be borrowed in Modern French words and eventually from Classical Latin, especially in the vocabulary of science, medicine, botany, and so on.
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Pirkei Avot / Ovos (Hebrew: Chapters of the Fathers, פרקי אבות) is a tractate of the Mishna composed of ethical maxims of the Rabbis of the Mishnaic period. It is the second-last tractate in the Mishnaic order Nezikin.
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off, down with, from here, at a distance; un (Prefix), free from

n. Ab, eleventh month of the Hebrew calendar

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