What is the meaning of “PAM” and what is it used for?

“PAM” is the abbreviation for Product Availability Matrix, which describes  – apart from the information you will find in the screenshot below – for which releases/versions of SAP products’ Maintream Maintenance is available. Products that are not covered by Mainstream Maintenance need to be maintained by Extended Maintenance or Customer Specific Maintenance.

Source (and access point to the PAM): https://support.sap.com/release-upgrade-maintenance/pam.html (retrieved 2017-01-05)