"flattened on the ends," 1705, from Medieval Latin oblatus "flattened," from Latin ob "toward" (see ob-) + -latus, abstracted from its opposite, prolatus "lengthened," from lātus (adj.) "broad, wide, extensive, large," Old Latin stlatus, from PIE *stleto-, suffixed form of root *stel- "to put, stand, put in order" (source also of words meaning "to spread, to extend," such as Old Church Slavonic steljo "to spread out," Armenian lain "broad").
"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."