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

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

With the magnetic needle they began to sail farther away from the shores, and since then they have discovered many new seas.

From Fables for Children, Stories for Children, Natural Science Stories, Popular Education, Decembrists, Moral Tales by Tolstoy, Leo, graf

Alternating Current Galvanometers.—For the detection of small alternating currents a magnetic needle or movable coil galvanometer is of no utility.

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