Source : Webster's Revised Unabridged Dictionary (1913)

Brobdingnagian \Brob`ding*nag"i*an\, a. [From Brobdingnag, a
   country of giants in ``Gulliver's Travels.'']
   Colossal; of extraordinary height; gigantic. -- n. A giant.
   [Spelt often {Brobdignagian}.]