Learning Preposition Basics words with Activity. A preposition is a word or group of words used before a noun, pronoun, or noun phrase to show direction, time, place, location, spatial relationships, or to introduce an object. Some examples of prepositions are words like "in," "at," "on," "of," and "to." There are about 150 prepositions in English. Yet this is a very small number when you think of the thousands of other words (nouns, verbs etc). Prepositions are important words. | Direction Scho