a slender bar of magnetized steel which, when mounted so as to swing freely on a pivot, will point along the line of the magnetic meridian toward the magnetic poles, approximately north and south: it is the essential part of a magnetic compass
"magnetic needle." YourDictionary, n.d. Web. 15 October 2018. <http://www.yourdictionary.com/magnetic-needle>.
magnetic needle. (n.d.). Retrieved October 15th, 2018, from http://www.yourdictionary.com/magnetic-needle
A slender bar of magnetized steel usually suspended on a low-friction mounting and used in various instruments, especially in the magnetic compass, to indicate the direction of the earth's magnetic poles.