ablation (n.)

word-forming element meaning "away, from, from off, down," denoting disjunction, separation, departure; from Latin ab (prep.) "off, away from" in reference to space or distance, also of time, from PIE root *apo- "off, away" (also the source of Greek apo "off, away from, from," Sanskrit apa "away from," Gothic af, English of, off; see apo-).

The Latin word also denoted "agency by; source, origin; relation to, in consequence of." Since classical times usually reduced to a- before -m-, -p-, or -v-; typically abs- before -c-, -q-, or -t-.

"person devoted to religious work," especially "child dedicated by his or her parents to monastic life and raised and trained in a monastery and held in monastic discipline," 1756, from Medieval Latin oblatus, noun use of Latin oblatus, variant past participle of offerre "to offer, to bring before," from ob- (see ob-) + lātus "carried, borne," used as past participle of the irregular verb ferre "to bear."

Presumably lātus was taken (by a process linguists call suppletion) from a different, pre-Latin verb. By the same process, in English, went became the past tense of go. Latin lātus is said by Watkins to be from *tlatos, from PIE root *tele- "to bear, carry" (see extol), but de Vaan says "No good etymology available."