Astronomy Dictionary Looking for the best Astronomy Dictionary in the Google Play? Check out our latest Astronomy Terms Dictionary... This glossary contains most of the terms that deal with the study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the atmosphere of Earth. It has over 1000 terms to familiarize yourselves with the world of Astronomy.the most frequent but however most difficult to find terms, express