Origin and history of prepositional

late 14c., preposicioun, in grammar, "indeclinable part of speech regularly placed before and governing a noun in an oblique case and showing its relation to a verb, adjective, or other noun," from Latin praepositionem (nominative praepositio) "a putting before, a prefixing," noun of action from past-participle stem of praeponere "put before," from prae "before" (see pre-) + ponere "put, set, place" (past participle positus; see position (n.)). In grammatical use, a loan-translation of Greek prothesis, literally "a setting before." Old English used foresetnys as a loan-translation of Latin praepositio.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).