北極星,指導者,指導原理
Polestar \Pole"star`\, n. 1. Polaris, or the north star. See {North star}, under {North}. 2. A guide or director.
polestar n : the brightest star in Ursa Minor; at the end of the handle of the little dipper; the northern axis of the earth points toward it [syn: {Polaris}, {North Star}, {pole star}, {polar star}]