Layer

n.	1.	One who, or that which, lays.
	2.	That which is laid; a stratum; a bed; one thickness, course, or fold laid over another; as, a layer of clay or of sand in the earth; a layer of bricks, or of plaster; the layers of an onion.
	3.	A shoot or twig of a plant, not detached from the stock, laid under ground for growth or propagation.
	4.	An artificial oyster bed.

Noun	1.	layer - single thickness of usually some homogeneous substance; "slices of hard-boiled egg on a bed of spinach" Synonyms: bed
	2.	layer - a relatively thin sheetlike expanse or region lying over or under another
	3.	layer - an abstract place usually conceived as having depth; "a good actor communicates on several levels"; "a simile has at least two layers of meaning"; "the mind functions on many strata simultaneously" Synonyms: stratum, level
	4.	layer - a hen that lays eggs
	5.	layer - thin structure composed of a single thickness of cells
Verb	1.	layer - make or form a layer; "layer the different colored sands"

layer - protocol layer

Appleton layer, F layer, Heaviside-Kennelly layer, Van Allen belt, arrange in layers, belt, bookie, chemosphere, delaminate, desquamate, exfoliate, flake, ionosphere, isothermal region, laminate, lay down, lay up, lower atmosphere, outer atmosphere, photosphere, scale, stratify, stratosphere, stratum, substratosphere, tropopause, troposphere, upper atmosphere