Astronomy \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.

Physical astronomy. See under Physical.

Source: Webster's Revised Unabridged Dictionary (1913)