Source : Webster's Revised Unabridged Dictionary (1913)

Colossus \Co*los"sus\, n.; pl. L. {Colossi}, E. {Colossuses}.
   [L., fr. Gr. ?.]
   1. A statue of gigantic size. The name was especially applied
      to certain famous statues in antiquity, as the Colossus of
      Nero in Rome, the Colossus of Apollo at Rhodes.

            He doth bestride the narrow world Like a colossus.
                                                  --Shak.

   Note: There is no authority for the statement that the legs
         of the Colossus at Rhodes extended over the mouth of
         the harbor. --Dr. Wm. Smith.

   2. Any man or beast of gigantic size.

Source : WordNet®

colossi
     See {colossus}

colossus
     n 1: someone or something that is abnormally large and powerful
          [syn: {giant}, {goliath}, {behemoth}, {monster}]
     2: a person of exceptional importance and reputation [syn: {behemoth},
         {giant}, {heavyweight}, {titan}]
     [also: {colossi} (pl)]