In telecommunications networks and Open Systems Architecture (for example, the OSI Model ) a Layer is a group of related functions that are performed in a given level in a hierarchy of groups of related functions.
In Object-oriented Design a layer is a group of Class es that have the same set of (link-time) module Dependencies to other Module s, i.e. a collection of Reusable components that are available for reuse in similar circumstances.
In Archaeology , a layer is a body of soil-material, often containing artefacts, deposited at the same time. See Stratigraphy .
