WordNet (r) 3.0 (2006):

Pythagoras
    n 1: Greek philosopher and mathematician who proved the
         Pythagorean theorem; considered to be the first true
         mathematician (circa 580-500 BC)

The Free On-line Dictionary of Computing (30 December 2018):

Pythagoras

    (Pythagoras of Samos, Ionia; about 569-475 BC) The
   Greek mathematician who founded a philosophical and religious
   school in Croton (now Crotone) in southern Italy.

   Pythagoras is most famous for Pythagoras's Theorem but other
   important postulates are attributed to him, e.g. the sum of
   the angles of a triangle is equal to two right angles.

   (2004-02-12)