Coupon rate is the fixed rate of interest that the company pays to the bond holders or debenture holders annually, semiannually or quarterly until it's maturity. It is predetermined as per the market interest rate and remains fixed during the life of bond. Coupon rate is not affected by change in market interest rate and market price of bond. Let's be clear from this example, A company issued 8%, 10-years bond at par value of $1000.
In this example, the rate 8% is the coupon rate at which the bond holders get annual payment of $80 (8% of $1000) until it's maturity of 10 years.