D defs.my
Entry 2 senses Webster, 1913

Astrolabe

/(ăs"trō̇*lāb)/ · As·tro·labe · IPA /ˈæs.tɹəˌleɪb/
01 n. An instrument for observing or showing the positions of the stars. It is now disused.
  1. 1.
    An instrument for observing or showing the positions of the stars. It is now disused.(Astron.)
  2. 2.
    A stereographic projection of the sphere on the plane of a great circle, as the equator, or a meridian; a planisphere.