As*tron"o*my (&?;), n. [OE. astronomie, F. astronomie, L. astronomia, fr. Gr. &?;, fr. &?; astronomer; 'asth`r star + &?; to distribute, regulate. See Star, and Nomad.] 1. Astrology. [Obs.]

Not from the stars do I my judgment pluck;
And yet methinks I have astronomy.
Shak.

2. The science which treats of the celestial bodies, of their magnitudes, motions, distances, periods of revolution, eclipses, constitution, physical condition, and of the causes of their various phenomena.

3. A treatise on, or text-book of, the science.

• The study of the physical universe beyond the Earth's atmosphere, and in particular the process of mapping location and properties of the matter and radiation in the universe. The study of the physical processes which control physical bodies in the universe is commonly called astrophysics. The physical description of the properties of the universe itself is called cosmology.