Advanced Power Management
Advanced power management (APM) is a technical standard for power management developed by Intel and Microsoft and released in 1992 which enables an operating system running an IBM-compatible personal computer to work with the BIOS (part of the computer's firmware) to achieve power management. Revision 1.2 was the last version of the APM specification, released in 1996.
Source: Wikipedia — Advanced Power Management (CC BY-SA 4.0)