Source : Webster's Revised Unabridged Dictionary (1913)

Mainland \Main"land`\, n.
   The continent; the principal land; -- opposed to {island}, or
   {peninsula}. --Dryden.

         After the two wayfarers had crossed from the peninsula
         to the mainland.                         --Hawthorne.

Source : WordNet®

mainland
     n : the main land mass of a country or continent; as
         distinguished from an island or peninsula