What does degaussing mean?
Degaussing is the process of eliminating or greatly reducing an unwanted magnetic field in an object. The technique has two principal applications. In naval engineering, ships are degaussed by passing electrical current through coils fitted around the hull, neutralizing the vessel's magnetic signature so that it will not trigger magnetic mines or attract magnetically fuzed torpedoes — a countermeasure developed during the Second World War. In computing and data security, degaussing refers to erasing magnetic storage media, such as tapes and hard drives, by subjecting them to a powerful, fluctuating magnetic field that scrambles recorded data beyond recovery. The term derives from the gauss, the older cgs unit of magnetic flux density named after the German mathematician Carl Friedrich Gauss. Degaussing remains a technical register word, familiar chiefly to naval architects, electronics technicians, and information-security professionals, but it names a concept with genuine historical and practical importance.
nounThe process of neutralizing or reducing an unwanted magnetic field in an object, such as a ship's hull or a data-storage medium, typically by exposing it to a varying magnetic field.
- The reduction or elimination of the residual magnetic field of a ship's hull to protect it against magnetic mines and torpedoes.
- The erasure of data from magnetic storage media (such as tapes or hard drives) by exposing them to a strong, fluctuating magnetic field.
"The naval engineers carried out routine degaussing of the vessel to reduce its vulnerability to magnetic mines."
"Before the convoy departed, each destroyer passed over a range where its degaussing was checked and adjusted."
"Secure disposal policies require certified degaussing of every retired hard drive before it leaves the facility."
During World War II, Allied ships survived deadly magnetic mines simply by being wrapped in cables and 'degaussed' — wiping their magnetic signature clean.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of degaussing
Degaussing derives from the verb degauss, formed from the prefix de- ('removal, reversal') plus gauss, the cgs unit of magnetic flux density named after the German mathematician and physicist Carl Friedrich Gauss (1777–1855). The compound arose in the early twentieth century, becoming widespread during the Second World War with the development of ship protection against magnetic mines. Cognate terms sharing the Gauss-derived root include gaussmeter and multiples such as kilogauss and milligauss.
Related word forms
How degaussing is actually used
A technical term used mainly in military, engineering, and information-security contexts; rare in everyday speech, where 'wiping' or 'erasing' is preferred for media and no everyday substitute exists for ships.
Easily confused with degaussing
Demagnetization is the broader general term for removing magnetism from any material, while degaussing specifically refers to doing so with a controlled alternating or decaying magnetic field, especially for ships or magnetic media.