The word legitimacy comes from the Latin word legitimare and it has two uses:

• Legitimacy (political science) is whether or not people accept the validity of a law or ruling or the validity of a governing regime. This concept has also been applied to other kinds of authority, such as that of an employer hiring workers. In the Marxian tradition, issues concerning the legitimacy of entire political-economic systems (such as capitalism) are discussed.

• In the common law tradition, legitimacy (law) describes the status of children who are born to parents that are legally married.