Source : Webster's Revised Unabridged Dictionary (1913)

Pythagorean \Pyth`a*go"re*an\, a. [L. Pythagoreus, Gr. ?.]
   Of or pertaining to Pythagoras (a Greek philosopher, born
   about 582 b. c.), or his philosophy.

         The central thought of the Pythagorean philosophy is
         the idea of number, the recognition of the numerical
         and mathematical relations of things.    --Encyc. Brit.

   {Pythagorean proposition} (Geom.), the theorem that the
      square described upon the hypothenuse of a plane
      right-angled triangle is equal to the sum of the squares
      described upon the other two sides.

Pythagorean \Pyth`a*go"re*an\, n.
   A follower of Pythagoras; one of the school of philosophers
   founded by Pythagoras.

Source : WordNet®

Pythagorean
     adj : of or relating to Pythagoras or his geometry; "Pythagorean
           philosophy"; "Pythagorean theorem"