The Collaborative International Dictionary of English v.0.48:

North \North\, a.
   Lying toward the north; situated at the north, or in a
   northern direction from the point of observation or
   reckoning; proceeding toward the north, or coming from the
   north.
   [1913 Webster]

   North following. See Following, a., 2.

   North pole, that point in the heavens, or on the earth,
      ninety degrees from the equator toward the north.

   North preceding. See Following, a., 2.

   North star, the star toward which the north pole of the
      earth very nearly points, and which accordingly seems
      fixed and immovable in the sky. The star [alpha] (alpha)
      of the Little Bear, is our present north star, being
      distant from the pole about 1[deg] 25', and from year to
      year approaching slowly nearer to it. It is called also
      Cynosura, polestar, and by astronomers, Polaris.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Polestar \Pole"star`\, n.
   1. Polaris, or the north star. See North star, under
      North.
      [1913 Webster]

   2. A guide or director.
      [1913 Webster]

WordNet (r) 3.0 (2006):

polestar
    n 1: 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, polestar]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "polestar":
   Aldebaran, Canicula, Dog Star, Hesper, Hesperus, Lucifer,
   North Star, Phosphor, Phosphorus, Polaris, Sirius, Venus, Vesper,
   artificial magnet, bar magnet, celestial body,
   center of attraction, center of consciousness, center of interest,
   comet, cynosure, daystar, electromagnetic lifting magnet,
   evening star, field magnet, fixed stars, focal point, focus,
   focus of attention, guiding star, heart, heavenly body,
   horseshoe magnet, hub, living sapphires, lodestar, lodestone,
   magnet, magnetic needle, magnetite, morning star, nerve center,
   orb, paramagnet, point of convergence, polar star, prime focus,
   seat, solenoid, sphere, starry host, stars