Several synonyms can be used to replace the word "bettered" in a sentence. "Improved" is the most commonly used synonym that can be used to describe something that has become better. Other synonyms for "bettered" include "progressed," "developed," "upgraded," "enhanced," and "elevated." If something has been upgraded or enhanced, it means that it has been made better than it previously was, which can also be referred to as the word "bettered." Using synonyms can make your writing more diverse and lessen repetition, but it is important to use words that fit the context of the sentence appropriately.