allative (adj.)

word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE root *ad- "to, near, at."

Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (as in affection, aggression). Also compare ap- (1).

In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but written forms in French were refashioned after Latin in 14c. and English did likewise 15c. in words it had picked up from Old French. In many cases pronunciation followed the shift. Over-correction at the end of the Middle Ages in French and then English "restored" the -d- or a doubled consonant to some words that never had it (accursed, afford). The process went further in England than in France, where the vernacular sometimes resisted the pedantic, resulting in English adjourn, advance, address, advertisement (Modern French ajourner, avancer, adresser, avertissement). In modern word-formation sometimes ad- and ab- are regarded as opposites, but this was not in classical Latin.

"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."