Level term life insurance has a level face amount of life insurance, with the possibility that premiums could increase after a certain number of years, such as 10, 20 or 30 years.
Some term life insurance policies are called guaranteed, but the insurance company just means that the premium won't go up unless it goes up for the whole group (which can be several times per year). And all term life policies have a big jump in premiums after the guaranteed period ends.
So, if you have a 20 year level term life insurance policy, the premium is guaranteed to remain the same for the 20 years, but upon renewal of the policy after 20 years, the premium may increase substantially each year thereafter.
Learn more about level term life insurance premiums and how they work.