prep ‧ o ‧ si ‧ tion /ˌprepəˈzɪʃ ə n/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Latin ; Origin: praepositio , from praeponere 'to put in front' ]
a word that is used before a noun, ↑ pronoun , or ↑ gerund to show place, time, direction etc. In the phrase ‘the trees in the park’, ‘in’ is a preposition.
—prepositional adjective