Source : Webster's Revised Unabridged Dictionary (1913)

Immensity \Im*men"si*ty\, n.; pl. {Immensities}. [L. immensitas:
   cf. F. immensit['e].]
   The state or quality of being immense; inlimited or
   immeasurable extension; infinity; vastness in extent or bulk;
   greatness.

         Lost in the wilds of vast immensity.     --Blackmore.

         The immensity of the material system.    --I. Taylor.

Source : WordNet®

immensity
     n : unusual largeness in size or extent [syn: {enormousness}, {grandness},
          {greatness}, {immenseness}, {sizeableness}, {vastness}]