preposition
noun
prep·o·si·tion ˌpre-pə-ˈzi-shən 
: a function word that typically combines with a noun phrase to form a phrase which usually expresses a modification or predication
prepositional
ˌpre-pə-ˈzish-nəl
adjective ˌpre-pə-ˈzi-shə-nᵊl
prepositionally adverb
Example Sentences
The preposition “on” in “The keys are on the table” shows location. The preposition “in” in “The movie starts in one hour” shows time.
Recent Examples on the Web Attention has clearly gone into each misspelling, unsuitable preposition, and grocer’s apostrophe. 
Colin Marshall, The New Yorker, 17 June 2022 Sometimes the ingredients are reversed and yoked by a preposition. New York Times, 23 Mar. 2022 Her schoolmate Stella Holtsclaw, a third grader, especially enjoys games during tutoring, like preposition bingo, and earning extra recess time. Chelsea Sheasley, The Christian Science Monitor, 15 Feb. 2022 Historian William Ian Miller attributes this new preposition to the fact that so few people are familiar with these old and specialized words. Melissa Mohr, The Christian Science Monitor, 27 Sep. 2021 The remaining brigade of 2,500 soldiers will still head to Kuwait to preposition in case they are needed. Conor Finnegan, ABC News, 14 Aug. 2021 Once, Turley recalls, Barr called him at 2 in the morning from a corporate jet to point out a missing preposition in a footnote on page 20. Manuel Roig-franzia, Washington Post, 15 Sep. 2020 Take that most school-marmish among them, that of never ending a sentence with a preposition. Joseph Epstein, National Review, 12 Sep. 2019 What if every college football school trademarked an appropriate conjunction, preposition, adverb, pronoun or interjection of three letters or shorter? Mike Finger, ExpressNews.com, 15 Aug. 2019 See More
Colin Marshall, The New Yorker, 17 June 2022 Sometimes the ingredients are reversed and yoked by a preposition. New York Times, 23 Mar. 2022 Her schoolmate Stella Holtsclaw, a third grader, especially enjoys games during tutoring, like preposition bingo, and earning extra recess time. Chelsea Sheasley, The Christian Science Monitor, 15 Feb. 2022 Historian William Ian Miller attributes this new preposition to the fact that so few people are familiar with these old and specialized words. Melissa Mohr, The Christian Science Monitor, 27 Sep. 2021 The remaining brigade of 2,500 soldiers will still head to Kuwait to preposition in case they are needed. Conor Finnegan, ABC News, 14 Aug. 2021 Once, Turley recalls, Barr called him at 2 in the morning from a corporate jet to point out a missing preposition in a footnote on page 20. Manuel Roig-franzia, Washington Post, 15 Sep. 2020 Take that most school-marmish among them, that of never ending a sentence with a preposition. Joseph Epstein, National Review, 12 Sep. 2019 What if every college football school trademarked an appropriate conjunction, preposition, adverb, pronoun or interjection of three letters or shorter? Mike Finger, ExpressNews.com, 15 Aug. 2019 See More Word History
Etymology
Middle English preposicioun, from Anglo-French preposicion, from Latin praeposition-, praepositio, from praeponere to put in front, from prae- pre- + ponere to put — more at position
First Known Use
14th century, in the meaning defined above
Kids Definition
preposition
noun
prep·o·si·tion ˌpre-pə-ˈzi-shən
: a word or group of words that combines with a noun or pronoun to form a phrase that usually acts as an adverb, adjective, or noun
"With" in "the house with the red door" is a preposition.