Line information database

The line information database (LIDB) is a collection of commercial databases used in the United States and Canada by telephone companies to store and retrieve Calling Name Presentation (CNAM) data used for caller ID services. In Canada, it is common for the client to apply their own Caller ID information, and this is allowed (and common in PBXs), provided the regulations regarding spoofing and fraud are not violated.

Source: Wikipedia — Line information database (CC BY-SA 4.0)