[, ] () a system of giving a grade to a bond according to how good and safe an investment it is considered to be; the grade that is given 债券评级（根据投资的稳健程度对所发行的债券的可靠程度进行评估，并标示其等级的制度）◆A triple-A bond rating guarantees a safe investment. 三 A 级债券评级保证投资的安全性。