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

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

From Time Magazine Archive

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

In its simple and original form the movable needle galvanometer consisted of a horizontal magnetic needle suspended within a coil of insulated wire by silk fibres or pivoted on a point like a compass needle.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various

It has no effect even upon the electrometer or the magnetic needle; its force is radiating, quite independent of light, but considerably increased by heat.

From Modern Magic by Vere, Maximilian Schele de