Greyshirting.
The NCAA has a five year rule to complete 4 years of eligibility. The five years has a clock and it starts ticking when you enroll in college. You can delay enrollment - you can not take more than 11 credits in a semester - up to one year before the clock starts ticking anyway.
There are some exceptions to the above - mission, serving in the armed forces, etc - but that's not what you are asking about.