1.verb(usually academic) To review materials already learned in order to make sure one does not forget them, usually in preparation for an examination.
"I need to study my biology notes."
2.verb(academic) To take a course or courses on a subject.
"I study medicine at the university."
3.verbTo acquire knowledge on a subject with the intention of applying it in practice.
"Biologists study living things."
4.verbTo look at minutely.
"He studied the map in preparation for the hike."
5.verbTo fix the mind closely upon a subject; to dwell upon anything in thought; to muse; to ponder.