Semester GPA
Your semester (or term) GPA covers only the courses you took in that one term. It's the most direct measure of how a single semester went.
Cumulative GPA
Your cumulative GPA is the credit-weighted average of every term you've completed. It's what appears on your transcript and what most scholarships and programs look at.
Why cumulative GPA moves slowly
Because cumulative GPA averages all your credits, a single strong or weak semester has less effect the more credits you've earned. Early semesters shape your cumulative GPA far more than later ones — which is why a strong start is so valuable.