\Neb"u*lar\, a.
Of or pertaining to nebul[ae]; of the nature of, or
resembling, a nebula.
{Nebular hypothesis}, an hypothesis to explain the process of
   formation of the stars and planets, presented in various
   forms by Kant, Herschel, Laplace, and others. As formed by
   Laplace, it supposed the matter of the solar system to
   have existed originally in the form of a vast, diffused,
   revolving nebula, which, gradually cooling and
   contracting, threw off, in obedience to mechanical and
   physical laws, succesive rings of matter, from which
   subsequently, by the same laws, were produced the several
   planets, satellites, and other bodies of the system. The
   phrase may indicate any hypothesis according to which the
   stars or the bodies of the solar system have been evolved
   from a widely diffused nebulous form of matter.