To review materials already learned in order to make sure one does not forget them, usually in preparation for an examination.
To take a course or courses on a subject.
To acquire knowledge on a subject with the intention of applying it in practice.
To look at minutely.
To fix the mind closely upon a subject; to dwell upon anything in thought; to muse; to ponder.
To endeavor diligently; to be zealous.

Mental effort to acquire knowledge or learning.
The act of studying or examining; examination.
Any particular branch of learning that is studied; any object of attentive consideration.
A room in a house intended for reading and writing; traditionally the private room of the male head of household.
An artwork made in order to practise or demonstrate a subject or technique.
The human face, bearing an expression which the observer finds amusingly typical of a particular emotion or state of mind.
A piece for special practice; an etude.
An academic publication.
One who commits a theatrical part to memory.
An endgame problem composed for artistic merit, where one side is to play for a win or for a draw.
(obsolete) A state of mental perplexity or worried thought.
Thought, as directed to a specific purpose; one's concern.