Committee on Union Security Identification Procedures (CUSIP)

The Committee on Uniform Security Identification Procedures (CUSIP) number identifies most securities, including U.S. government and municipal bonds. CUSIP numbers are unique nine-character alphanumeric identifiers assigned to each series of securities.

Source: http://investor.gov/glossary/glossary_terms/committee-union-security-identification-procedures-cusip#.Us2ffmRDuEg