Meaning of “better” - Learner’s Dictionary

better

noun uk us /ˈbetər/
for the better

If a situation changes for the better, it improves:

Their relationship has changed for the better.
get the better of sb

If a feeling gets the better of you, it becomes too strong to control:

Curiosity finally got the better of her and she opened the letter.

(Definition of “better noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)