magnetic needle

American  

noun

1. a slender magnetized steel rod that, when adjusted to swing in a horizontal plane, as in a compass, indicates the direction of the earth's magnetic fields or the approximate position of north and south.

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magnetic needle British  

noun

1. a slender magnetized rod used in certain instruments, such as the magnetic compass, for indicating the direction of a magnetic field

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Etymology

Origin of magnetic needle

First recorded in 1840–50

Example Sentences

See Examples For:

magnetic needle

Finding the magnetoreceptors responsible for triggering these neurons has been like looking for a magnetic needle in a haystack.

From Science Magazine ● Jun. 23, 2016

Last week Bendix Aviation Corp. announced a new automatic compass that makes the old magnetic needle* look as obsolete as a warrior's spear.

From Time Magazine Archive

He said: "Nothing must deflect the magnetic needle."

From Time Magazine Archive

Astatic, a-stat′ik, adj. having a tendency not to stand still: losing polarity, as a magnetic needle.

From Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) by Various

An electrical machine or a battery of Leyden jars can be made to give out an electric current, and this current will affect a magnetic needle in the same way that a battery current will.

From The Story of Great Inventions by Elmer Ellsworth Burns