To resign or resignation, in English: resign and resignation, is to resign a position. Etymologically this term comes from the Latin dimĭttĕre, which means "leave", "dismiss", "deliver".
Resignation is a concept that refers to the voluntary resignation or abandonment of a job, a position, a commission, etc.
A resignation may occur when a person holding a position won by election or appointment leaves it, but it is considered that leaving a position by expiration of time is not a resignation. Abdication is the equivalent of resignation in a reigning monarch or other unelected forms of government.
When a person resigns he is concretizing a unilateral act: whoever holds the position, decides to resign. In this way the resignation differs from a dismissal, where an authority or a hierarchical superior forces the person to leave his position.
However, resignations are presented that are not unilateral but consensual. For example, the technical director of a sports team may meet with the directors of his club after suffering a series of defeats and convince him to resign.
There are even cases where resignation is demanded by an authority, which makes it look like a dismissal but has different legal consequences (when resigning, a person does not receive compensation). The president of a state may not be satisfied with the work of one of its ministers and in this situation, the president demands the resignation of the ministers.
In the case of U.S. President Richard Nixon he resigned from office due to the Watergate scandal when he was almost certain he would be subject to the Impeachment procedure by the U.S. Congress.