A savings product that locks money for a fixed term in exchange for a guaranteed rate.
A certificate of deposit pays a fixed interest rate if you leave the money untouched for a set term, from a few months to several years. Withdrawing early usually triggers a penalty. CDs suit money you know you won't need until a specific date and want protected from market risk.
A one-year CD might lock in a fixed rate that you keep even if savings rates fall during the year.