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A layer of deposits found on archaeological excavation isolated as a single context in the stratigraphy of the site

A layer hen, a hen raised to produce eggs.

Layer (abstraction), In abstraction, a layer is an abstract place conceived as having depth.

Stratum, a layer of rock or soil with internally consistent characteristics.

Thermocline, a layer within a body of water where the temperature changes rapidly with depth.

Layering, a technique for plant propagation.

Layered hair, a popular hair styling technique.

Layer de la Haye is a village in Essex, United Kingdom.

Abstraction layer. 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.

Layer (stack frame), In computer programming a layer is (also) an abstraction of the type of a stack frame of a run-time call stack of a thread.

2D computer graphics#Layers, layers in 2D computer graphics

Layers %28Digital image editing%29

layer (object-oriented design). In object-oriented design, a layer is a group of classes that have the same set of (link-time) module dependencies to other modules, i.e. a collection of reusable components that are available for reuse in similar circumstances.

DVD layer, such as in DVD Dual layer recording

Appleton Layer, or F region (telecommunications)

Layer (HTML tag), in web design, was a
-like tag, unique to Netscape browsers. It has been deprecated and fallen out of use.

In instructional design a layer is an element of the design architecture representing a funtion carried out by an instructional artifact. Design layers are characterized by coherent design languages that are used to express different layers of the design.