Definition of over preposition in oxford advanced learners dictionary. We use over as a preposition and an adverb to refer to something at a higher position than something else, sometimes involving … In or at a position above or … Meaning, pronunciation, picture, example sentences, grammar, usage … Downward from an upright position Over synonyms, over pronunciation, over translation, english dictionary definition of over. How to use over in a sentence. The meaning of over is across a barrier or intervening space; In an upward and forward direction across something; Across the goal line in football.