To obstruct, cover, or otherwise block (an opening, a portion of an image, etc.).
To absorb, as a gas by a metal.
To fill a hole or cavity, or block (an opening or passage), as with a plug.
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.