Real Dictionary

white dwarf in American English
a planet-sized, very dense, collapsed star, the fuel of which has been exhausted: initially very bright and hot, it gradually evolves into a black dwarf
noun: a star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars, beginning hot and white and ending cold and dark (black dwarf)

white dwarf in British English
noun: one of a large class of small faint stars of enormous density (on average 108 kg/m3) with diameters only about 1 per cent that of the sun, and masses less than the Chandrasekhar limit (about 1.4 solar masses). It is thought to mark the final stage in the