The natural hierarchy of social status and dominance occurring in a group of birds.
The usually informal hierarchy of authority or command, often partial or approximate, as determined by the especially natural propensity for domination of different members of a specific group over each other, such as older brothers and sisters over their younger siblings.
A class of society composed of people with similar social, cultural, or economic status.
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 layer of vegetation, usually of similar height.
The level of accuracy of a computer's clock, relative to others on the network.
A layer of tissue.