Better and Higher-grade

Better adjective - (comparative of `good') superior to another (of the same class or set or kind) in excellence or quality or desirability or suitability; more highly skilled than another.

Higher-grade and better are semantically related. In some cases you can use "Higher-grade" instead an adjective "Better".

Better and higher-grade are semantically related. You can use "Better" instead an adjective phrase "Higher-grade".