The International Astronomical Union defines a planet as a celestial body that orbits the sun, is massive enough that gravity has forced it into a spherical shape, and has cleared away other objects ...

The definition of "planet" has for some time been the subject of intense debate. Although the word dates back thousands of years, no officially decreed scientific definition of "planet" existed before ...

THERE is every reason to suppose that this dictionary will quickly assume and long retain a place on the most easily accessible shelves of both private and public libraries. The translation of ...