The Seniority reference article from the English Wikipedia on 24-Apr-2004
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Seniority

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Seniority is the concept of a person or group being in charge or in command of another person or group. This control is often granted to the senior person(s) due to experience or length of service in a given position, but it is not uncommon for a senior person(s) to have less experience or length of service than their subordinates.

Subordinates are generally expected to follow the actions, orders, or requests of those senior to them with little or no question.

Seniority is present every day, be it between parents and children, sibilings of different ages, workers and their managers, and is a large part of the military and para-military command structure.

See also: authority