Source : Webster's Revised Unabridged Dictionary (1913)

Cosmology \Cos*mol"o*gy\ (k[o^]z*m[o^]l"[-o]*j[y^]), n. [Gr.
   ko`smos the world + -logy: cf. F. cosmologie.]
   The science of the world or universe; or a treatise relating
   to the structure and parts of the system of creation, the
   elements of bodies, the modifications of material things, the
   laws of motion, and the order and course of nature.

Source : WordNet®

cosmology
     n 1: the metaphysical study of the origin and nature of the
          universe
     2: the branch of astrophysics that studies the origin and
        evolution and structure of the universe [syn: {cosmogony},
         {cosmogeny}]