magnetic field

American  

noun

1. a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on any other magnet, electric current, or moving charged particle.

2. magnetic intensity.

---

magnetic field British  

noun

1. a field of force surrounding a permanent magnet or a moving charged particle, in which another permanent magnet or moving charge experiences a force Compare electric field

---

magnetic field Scientific  

1. A field of force associated with changing electric fields, as when electric charges are in motion. Magnetic fields exert deflective forces on moving electric charges. Most magnets have magnetic fields as a result of the spinning motion of the electrons orbiting the atoms of which they are composed; electromagnets create such fields from electric current moving through coils. Large objects, such as the earth, other planets, and stars, also produce magnetic fields.

2. See Note at magnetism

3. See magnetic field strength

---

magnetic field Cultural  

1. A magnetic field is said to exist in a region if a force can be exerted on a magnet. If a compass needle is deflected when it is put at a particular location, we say a magnetic field exists at that point, and the strength of the field is measured by the strength of the force of the compass needle. The Earth, the sun, and the Milky Way galaxy all have magnetic fields. All known magnetic fields are caused by the movement of electrical charges. Electrons in orbit in atoms give rise to magnetic fields, so that every atom is, like the Earth, surrounded by a magnetic field. (See magnet and magnetism.)

---

Etymology

Origin of magnetic field

First recorded in 1835–45

Example Sentences

A horizontal magnetic field generated a two dimensional flow, while an array of rods was used to disturb it.

From Science Daily • Jun. 3, 2026

According to a study published in Science, pigeons may use specialized immune cells in their livers to detect Earth's magnetic field, providing them with an internal navigation system.

From Science Daily • May 31, 2026

In 2012, researchers at the Wisconsin Plasma Physics Laboratory observed magnetic field behavior that existing theories could not explain.

From Science Daily • May 26, 2026

By studying the angles of the auroras in those images and mapping them along Earth's magnetic field lines, the researchers were able to estimate how high the glowing structures reached into the atmosphere.

From Science Daily • May 22, 2026

Only one problem: Mars doesn't have a magnetic field.

From "The Martian" by Andy Weir