white dwarf

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The collapsed remnant core of a low-mass star that has ejected its outer layers and can no longer sustain nuclear fusion. White dwarf stars are extremely dense, having no empty space between atoms, but lack the mass to reach the even more extremely dense states of a neutron star or black hole.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun astronomy A dying star of low or medium mass, more solid and dense but less bright than the sun.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a faint star of enormous density