I couldn't explain it very clearly to the people who asked me what I did to fix the monitor problem when I fixed it just by clicking this “degauss“ button on their screen. I knew and learned this term, gauss, in my physical class at high school but only in Chinese. And never thought I need it in English one day. So here is what I found:
Gauss, originally came from the name of German mathematician and astronomer known for his contributions to algebra, differential geometry, probability theory, and number theory, expresses the centimeter-gram-second unit of magnetic induction. The following definition explains it in more detail.
quote from The Sharpened Glossary
Ever wonder what that "degauss" button on your monitor does besides make a buzzing noise and cause the screen to go crazy for a second? Though that's its main purpose, the degauss button has another useful feature. To understand it, you'll first need to know that the earth has natural magnetic fields. The magnetic charges from these fields can build up inside your monitor, causing a loss of color accuracy. Degaussing scares the bad magnetism out of the monitor and fills it with good karma. If your monitor doesn't have a degauss button, fear not -- many new monitors automatically degauss themselves. If you have a flat-panel display, there is no degauss button because magnetism doesn't build up in flat screen displays.