Definition - What does Program Layer mean?
A program layer is an independent operating component of a software program. It works with the rest of the information (and other program layers) according to a certain sequence of data manipulation tasks. Each layer typically interacts with the layers above and below it.
Techopedia explains Program Layer
Program layers can be though of as independent functional parts of an application. For example, a user interface (UI) layer, a business logic layer, and a database layer. Each of these layers can be implemented by different development teams without affecting other layers' functionality.
By dealing with the relevant functions and data from the program layers just above and below it, the combined tasks can give the output expected of the overall system.