Generally speaking, to demagnetize any device, object, or material, commonly by means of electric coils. Degaussing was at one time (and may still be) performed on the hulls of naval vessels, as a means of removing any magnetic influence a metal hull might have on a magnetic mine (such as causing the mine to explode). Many electric and electronic devices build up magnetic charges. Often, degaussing needs to be performed on an audio tape player, as built-up magnetism affects the playback of recordings. On a computer monitor, magnetic buildup distorts the appearance of displayed colors, and degaussing can usually correct such display problems. The term degaussing also refers to the erasure of data stored on magnetic media, such as audio and video tapes, magnetic computer cartridges, and so forth.
The term degauss derives from the name of the German mathematician and scientist Karl Friedrich Gauss (1777:1855) who in the 1830s carried out some of the earliest and most influential research on magnetism.