Gilts are government bonds.
When you buy a gilt, you’re lending money to the UK government. When the gilt matures, the government repays you the face value, or nominal value, of the gilt.
Throughout the life of the gilt, the government also pays you coupons. These are regular dividends paid out every six months at a pre-determined rate.
Let’s say you hold £1,000 nominal of £TR28 - 6% Gilt 2028. It matures on 7th December 2028, and offers an annual dividend rate of 6%.
You’d receive £30 every six months until December 2028, at which point the government would pay you one final dividend of £30, as well as repaying you the £1,000 principal.