ab-

1.
a formal element occurring in loanwords from Latin, where it meant “away from”:
abdicate; abolition.
Also, a-, abs-.
Origin
< Latin ab (preposition and prefix) from, away, cognate with Greek apó, Sanskrit ápa, German ab, English of1, off
British Dictionary definitions for ab-

ab-1

prefix
1.
away from; off; outside of; opposite to: abnormal, abaxial, aboral
Word Origin
from Latin ab away from

ab-2

prefix
1.
denoting a cgs unit of measurement in the electromagnetic system: abvolt
Word Origin
abstracted from absolute
Word Origin and History for ab-

word-forming element meaning "away, from, from off, down;" from Latin ab-, ab "off, away from," from PIE root *apo- (see apo-). Reduced to a- before -m-, -p-, or -v-; sometimes abs- before -c- or -t-.

ab- in Medicine

ab- 1
pref.
Away from: abaxial.

ab- 2
pref.
Used to indicate an electromagnetic unit in the centimeter-gram-second system: abcoulomb.