Full Idea
Aristotle praises the Pythagoreans for being the first to offer definitions.
Gist of Idea
The Pythagoreans were the first to offer definitions
Source
report of Vassilis Politis (Aristotle and the Metaphysics [2004]) by Vassilis Politis - Aristotle and the Metaphysics 2.4
Book Reference
Politis,Vasilis: 'Aristotle and the Metaphysics' [Routledge 2004], p.62
A Reaction
This sounds like a hugely important step in the development of Greek philosophy which is hardly ever mentioned.