Search Result for "hipparchus": 
Wordnet 3.0

NOUN (1)

1. Greek astronomer and mathematician who discovered the precession of the equinoxes and made the first known star chart and is said to have invented trigonometry (second century BC); 



WordNet (r) 3.0 (2006):

Hipparchus
    n 1: Greek astronomer and mathematician who discovered the
         precession of the equinoxes and made the first known star
         chart and is said to have invented trigonometry (second
         century BC)