• A layer of dieposits found on archaeological excavation isolated as a single context in the stratigraphy of the site
• A layer hen, a hen raised to produce eggs.
• 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.
• Layering (clothing), the wearing of multiple layers of clothing for practical or fashion purposes

Places:

• Layer de la Haye is a village in Essex, England.

In fiction:

• Layer, a scantily-clad female Maverick Hunter in the Mega Man X series. She works as a Navigator and has a crush on the character Zero.

In computing and technology:

• Abstraction layer
• Layer (stack frame)
• Networking:
• OSI model layers
• Internet protocol suite layers
• 2D computer graphics#Layers, layers in 2D computer graphics
• Layers %28digital image editing%29
• layer (object-oriented design).
• DVD layer, such as in DVD Dual layer recording
• Appleton Layer, or F region (telecommunications)
• Layer (HTML tag) was an <iframe>-like tag, unique to Netscape 4 browsers. It has been deprecated and fallen out of use.
• In instructional design a layer is an element of the design architecture representing a function carried out by an instructional artifact. Design layers are characterized by coherent design languages that are used to express different layers of the design.
• A subset of related objects on a CAD drawing which can be viewed and manipulated separately from the whole drawing. Layers are usually organised to one of several recognised standard, such as ISO 13567.