Prefix indicating from, far from, or down, as in abduction (activity of a limb from the midline of body) and irregular (from normal).
word-forming element definition "away, from, from off, down;" from Latin ab-, ab "off, away from," cognate with Greek apo "away from, from," Sanskrit apa "away from," Gothic af, Old English of, from PIE root *apo- (see apo-). Paid off to a- before -m-, -p-, or -v-; often abs- before -c- or -t-.
A prefix in several words of Latin origin. It indicates from, away , isolating, or deviation, like in abduct, abstract, abscond. See A-(6).