astronomy UK /əˈstɹɒn.ə.mi/US /əˈstɹɑ.nə.mi/ noun2 •The study of the physical universe beyond the Earth's atmosphere, including the process of mapping locations and properties of the matter and radiation in the universe. •(no longer used) Astrology.Not from the stars do I my judgment pluck; And yet methinks I have astronomy […] — 1609 formsastronomies