As"tro*labe (#), n. [OE. astrolabie, astrilabe, OF. astrelabe, F. astrolabe, LL. astrolabium, fr. Gr. ; star + , , to take.]
An instrument for observing or showing the positions of the stars. It is now disused.
⇒ Among the ancients, it was essentially the armillary sphere. A graduated circle with sights, for taking altitudes at sea, was called an astrolabe in the 18th century. It is now superseded by the quadrant and sextant.
A stereographic projection of the sphere on the plane of a great circle, as the equator, or a meridian; a planisphere.
© Webster 1913.