To permanently close or block (a road or path); to legally extinguish a right of way.
To increase the aperture of a photographic lens, moving from an f/stop represented by a higher number to an f/stop represented by a lower number and causing more light to pass into the camera.
To fill a hole or cavity, or block (an opening or passage), as with a plug.
The removal of a block or blockage.
To remove or clear a block or obstruction from.
In whist, to throw away a high card so as not to interrupt one's partner's long suit.
To free or make available.
To enable communication again, via telephone, instant messaging, etc., with (somebody previously blocked).