Supernumerary is a member of the staff or an employee who works in a public office but is not part of the manpower complement.
The terms supernumerary and its counterpart, numerary,originated in Spanish and Latin American academy and government; and it is now also used in countries all over the world, like France, the US, England, Italy, etc.
Supernumerary is distinguished from numerary which is a civil designation for persons who are incorporated in a fixed or permanent way to a society or group: regular member of the working staff; permanent staff or member.
There are many types of supernumeraries, depending on the society where they belong:
supernumerary accountants, [1]
supernumerary judges or magistrates, [2]
supernumerary members of a Council of the Royal Academy of Engineering. [3]
The majority of the lay members are "supernumeraries," who are involved in Opus Dei's activities but do not make a commitment of celibacy.
The distinction is in their availabilty to direct and assist in the apostolic activities of the prelature.
While the women numeraries can't be ordained (as with the Roman Catholic priesthood), they receive the same philosophical and theological formation the male numeraries receive.