What is the English term called when you say good better best?

The English term for saying "good, better, best" is called a comparative and superlative adjective.

* Good is the positive form of the adjective.

* Better is the comparative form, used to compare two things.

* Best is the superlative form, used to compare more than two things or to indicate the highest degree of something.

This is a common pattern in English grammar for many adjectives.