OODBMS stands for "object-oriented database management system". Unlike relational databases, object-oriented databases are not organized in rows and columns. Instead, the objects' attributes and services are stored together. An OOBDMS can handle many types of complex data structures that would be troublesome or impossible under the relational model, including (perhaps most importantly) multimedia data types.

While object-oriented programming is all the rage for corporations building large, complex information systems, object-oriented database systems have not yet sufficiently caught on to replace relational database systems. Nonetheless, most RDBMS products have begun to incorporate object-oriented capabilities.

Sources: (1) Analysis and Design of Information Systems by Arthur Langer (2001); (2) The Computer Desktop Encyclopedia, 2nd Ed., by Alan Freedman (1999).