A preposition is a word that shows the relationship between its object and another word in the sentence.Examples:She brought some flowers forher mother. (the preposition 'for' connects its object 'mother' to the noun 'flowers')He ran with the scissors in his hand. (the preposition 'with' connects its object 'scissors' to the verb 'ran')A man in a raincoat came in. (the preposition 'in' connects its object 'raincoat' to the noun 'man')