Answer:
He coined the name "astronomy"
Step-by-step explanation:
Pythagoras was a Greek philosopher who made important developments in mathematics, astronomy, and the theory of music - yes. But he didn't coin the word/phrase "astronomy". That word was used much later by a group of Greeks (that were either poets or astronomers, I'm not sure). Pythagoras's focus and contributions were mostly focused on mathematics (Pythagoras Theorem).
Hope this helps! :D