A component of the circulatory system, such as an artery, capillary, or vein, that carries blood.
A layer of tissue.
One of several parallel horizontal layers of material arranged one on top of another.
A layer of sedimentary rock having approximately the same composition throughout.
Any of the regions of the atmosphere, such as the stratosphere, that occur as layers.
A class of society composed of people with similar social, cultural, or economic status.
A layer of vegetation, usually of similar height.
The level of accuracy of a computer's clock, relative to others on the network.