Letters (e.g., "AAA," "AA," etc.) that are assigned to bonds to express their relative probability of default; letter grades that designate investment quality.
A system for measuring the relative credit worthiness of bond issues using rating symbols, which range from the highest investment quality (least investment risk) to the lowest investment quality (greatest risk).
Rating for bonds to be issued that primarily reflects the ability of the issuer to repay the bonds. Better bond ratings result in lower interest rates for the bonds issued. (House Fiscal Analysis Department)