stop up

Definitions

1. 1

   To fill a hole or cavity, or block (an opening or passage), as with a plug.

   • So then we […] scratched around and found an old tin washpan, and stopped up the holes as well as we could.
2. 2

   To permanently close or block (a road or path)

   To permanently close or block (a road or path); to legally extinguish a right of way.

3. 3

   To increase the aperture of a photographic lens, moving from an f/stop represented by a…

   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 stop down means to narrow the aperture; to stop up or open up means to expand it.

The neighborhood

• antonymstop downantonym(s) of “increase the aperture of a photographic lens”