compass needle

基本解释

Here is the set of points that defines the compass needle.
这里是点的集合，它定义罗盘针。
A compass needle always points to the north.
罗盘的指针总是指向北方。
The massive magnetic field of a powerful MRI machine aligns the nuclei of the atoms in the same direction, much as a magnet pulls a compass needle.
一台功能强大的磁共振成像仪的强大磁场能使原子核往同一方向排列成行，就好像磁铁吸引罗盘的指针一样。

Suddenly we were coming about again, and I watched the compass needle whirl to its new heading.
NPR: Excerpt: 'Skybreaker'
In 1745, an English physicist named Gowin Knight developed a compass with a steel needle, which retained its magnetism longer.
FORBES: Magazine Article
Once again, we accompany Captain Jack Sparrow (Johnny Depp) as he pursues his fate—or the needle of his compass—across the waters.
NEWYORKER: Pirates of the Caribbean: Dead Man's Chest