What is the interest rate the bond issuer pays to the bondholder called?

The coupon rate or maturity rate is what the interest rate the bond issuer pays to the bond holder is called.

The coupon rate is the amount the bond paid on the date it was issued to the investor. The maturity rate is the final amount that was paid from a loan or other financing measure. Both are interest rates that are paid to the bond holder depending on when they purchase/finish with their bond.