magnetic needle

magnetic-needle的词性：
n.（名词）

1. 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.
磁针：一根通常悬浮于摩擦很小的底座上被磁化过的小钢条，并用于多种指示地球磁极方向的仪器，尤指磁性罗盘上