The period through which you agree to pay the premium for the insurance cover. It is measured in number of years.
Usually, the premium for a policy is paid as long as the insurance cover is active. So in such cases, the premium payment term is equal to the policy term. However, there are options available where you can have a long term insurance cover, but pay off premiums faster in a shorter number of years. Kind of a staggered advance of the premium.
This is particularly useful for long term insurance policies.
Always have clear reasons to pay the premium in advance in a shorter number of installments. If required ensure you calculate the Net Present Value for all the premium payouts between the options you are comparing.
In case you are buying term insurance at the age of 30 years until the age of 75 years. Here you have options to either pay the premium till the age of 75 (regular pay - for the entire coverage duration) or pay off the premium in a shorter period (called limited pay) of say 1, 5, 10, 15 years or pay till the age of 60 years (30 years).