Meaning : That which has mass and occupies space.
Example :
Physicists study both the nature of matter and the forces which govern it.
Meaning : A problem.
Example :
Is anything the matter?.
Meaning : (used with negation) having consequence.
Example :
They were friends and it was no matter who won the games.
Meaning : Written works (especially in books or magazines).
Example :
He always took some reading matter with him on the plane.