magnetism
Americannoun
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the property of attraction displayed by magnets
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any of a class of phenomena in which a field of force is caused by a moving electric charge See also electromagnetism ferromagnetism diamagnetism paramagnetism
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the branch of physics concerned with magnetic phenomena
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powerful attraction
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The properties or effects of magnetic fields.
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The force produced by a magnetic field.
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See more at magnetic field
Closer Look
Magnetism is intimately linked with electricity, in that a magnetic field is established whenever electric charges are in motion, as in the flow of electrons in a wire, or the movement of electrons around an atomic nucleus. In atoms, this invisible field consists of closed loops called lines of force that surround and run through the atom. Magnetic regions where lines of force come together densely are called north and south poles. In substances in which the magnetic fields of each atom are aligned, the magnetic field causes the entire substance to act like single magnet—with north and south poles and a surrounding magnetic field. Permanent magnets are made of substances that retain this alignment. If a magnet is cut in two, each piece becomes a separate magnet with two poles. A coil of wire wrapped around an iron core can be made magnetic by running electric current through it; the looping electrons then create a magnetic field in just the same way as the spinning electrons in individual atoms. As long as current flows, the coil remains magnetized. Such magnets, called electromagnets, are used in many devices such as doorbells and switches. The connection between electric and magnetic fields is not one of cause and effect, however. Einstein showed that both the magnetic and electric fields are part of a single electromagnetic field, described by a single mathematical object called a tensor. Observers in different reference frames will not observe the same separate values for electric and magnetic fields, but will observe identical electromagnetic tensors. Whether or not magnetic monopoles (elementary particles carrying an isolated north or south magnetic “charge,” analogous to positive or negative electric charge) actually exist remains unknown; though they are predicted by some theories, none have been detected.
Other Word Forms
- magnetist noun
Etymology
Origin of magnetism
From the New Latin word magnētismus, dating back to 1610–20. See magnet, -ism
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Potential uses include micro and nanoelectromechanical systems, where wear limits device lifespan, as well as magnetic bearings, vibration isolation systems, and ultra-thin magnetic materials where motion and magnetism are closely linked.
From Science Daily • Mar. 22, 2026
Instead of involving magnetism, it can arise from electron charge.
From Science Daily • Mar. 16, 2026
Today, Mars has scattered regions of magnetism in its crust and a constantly shifting magnetic field created when solar wind interacts with charged particles in the planet's upper atmosphere.
From Science Daily • Mar. 14, 2026
The new research offers an explanation for how the Moon could briefly generate and preserve such intense magnetism.
From Science Daily • Feb. 26, 2026
Halley was interested in terrestrial magnetism and had an idea that variations in magnetism from place to place around the globe might, if they were first mapped accurately, be used as a means of navigation.
From "The Scientists" by John Gribbin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
