Adjacent corners of a square share one side. Opposite corners share no sides.
The corner. (As in the corner or the desk, book, or a street corner)
If you mean the screen size, then it is measured by the diagonal of the screen from corner to corner.
It means you may not park your car between the sign that says "No parking here to corner" and the corner.
It usually means you have something on the corner of your mouth.
Corner Infielder
Corner Blacksmith
corner kick
the corner
Beautiful corner
It is a 'corner' of a polygon.
Corner infielder
it means up ur but and around THE CORNER