DB2 <database> A {relational database} from {IBM}. When running under IBM's MVS ({Multiple Virtual Storage}) {operating system}, DB2 is implemented on top of {VSAM} and uses its underlying data structures. DB2, later called "DB2 Universal DataBase", also runs under {windows NT}, {AIX}, {Solaris} and, most recently, {Linux}. [Details? Was there a "DB1"?] (1999-02-01)