Definition of "astronomy" []

• The scientific study of matter in outer space, especially the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial bodies and phenomena. (noun)
• A system of knowledge or beliefs about celestial phenomena: the various astronomies of ancient civilizations. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Shortly after Joe Haldeman received a Bachelor of Science degree in astronomy from the University of Maryland, he was drafted into the army where he served (and received a Purple Heart medal) as a combat engineer in Vietnam."
• "As a result, my trying to keep up with what's going on in astronomy is largely an internet affair."
• "Your duties will consist of instructing others in that new science which you call astronomy and in applying it for the welfare of humanity."