General English

  • noun the scientific study of the stars, sun and planets

General Science

  • noun the study of natural objects in space, including earth


  • The study of objects in the heavens and of the Earth as an object in space, including their history and development and that of the universe as a whole. Astronomy is perhaps the most ancient of the sciences, since all known cultures have or have had ideas about the Cosmos. Modern astronomy is related closely to other sciences, especially physics, and has many subdivisions, most notably cosmology and astrophysics.

Origin & History of “astronomy”

Astronomy comes via Old French and Latin from Greek astronomíā, a derivative of the verb astronomein, literally ‘watch the stars’. Greek ástron and astḗr ‘star’ (whence English astral (17th c.) and asterisk (17th c.)) came ultimately from the Indo-European base *ster-, which also produced Latin stella ‘star’, German stern ‘star’, and English star. The second element of the compound, which came from the verb némein, meant originally ‘arrange, distribute’.

At first, no distinction was made between astronomy and astrology. Indeed, in Latin astrologia was the standard term for the study of the stars until Seneca introduced the Greek term astronomia. When the two terms first coexisted in English (astrology entered the language about a century later than astronomy) they were used interchangeably, and in fact when a distinction first began to be recognized between the two it was the opposite of that now accepted: astrology meant simply ‘observation’, whereas astronomy signified ‘divination’. The current assignment of sense was not fully established until the 17th century.