What Does .MDB File Format Mean?
MDB is the default file format used in Microsoft Office Access, up to Access 2003. In the 2007 and 2010 versions, however, Access uses the newer ACCDB file format as the default.
The file extension for the MDB file format is .mdb.
Techopedia Explains .MDB File Format
Microsoft Office Access is Microsoft’s answer to providing a small database engine. It enables users with little knowledge of database administration to quickly set up their own database. The following versions of Access use the MDB file format as default: Access 95, 97, 2000 and 2003.
In 2007, Microsoft introduced a new file format (the ACCDB file format) with the 2007 version of Access. Access 2010 continues to use the same format. However, the 2007 and 2010 versions are also compatible with the older MDB format.