layer(redirected from columnar layer)
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1. one of four or more levels of vegetation defined in ecological studies: the ground or moss layer, the field or herb layer, the shrub layer, and one or more tree layers
2. a laying hen
a. a shoot or branch rooted during layering
b. a plant produced as a result of layering
One of the divisions within which components or functions are isolated in a computer system with layered architecture or a communications system with layered protocols.
A tabular body of rock, ice, sediment, or soil lying parallel to the supporting surface and distinctly limited above and below.
One of several strata of ionized air, some of which exist only during the daytime, occurring at altitudes between 30 and 250 miles (50 and 400 kilometers); the layers reflect radio waves at certain frequencies and partially absorb others.
The stratum of weld metal consisting of one or more passes and lying parallel to the welding surface.
1. A layer of masonry units running horizontally in a wall or, much less commonly, curved over an arch; it is bonded with mortar.
2. A continuous row or layer of material, as shingles, tiles, etc.
3. In concrete construction, one of several horizontal layers making up a lift, 5. For specific types, see band course, base course, belt course, blocking course, bond course, coping course, corbel course, dog-tooth course, masonry course, random course, sill course, springing course, staggered course, stringcourse, tumbling course.
layer(1) One of several "drawing boards" or "canvasses" for creating elements in a picture. See layers and flatten layers.
(2) One of several levels in a communications protocol. See OSI model.