supernumerary

1. (film, theater) An extra or walk-on, often non-speaking, in a film or play; a spear carrier.Examples: "[A] minor actor or supernumerary often has a better opportunity to watch great actors than the great actors themselves."; "Though little is known about Noble Luke Usher before his first recorded performance in Washington, D.C., in 1800, it is certain that he made the rounds of the eastern theatres as a supernumerary before as well as after that year."Synonyms: supe, super

2. (zoology) An animal which has not formed a pair bond and is therefore single.Examples: "The best evidence so far that social supernumeraries are physically capable of bettering their lot concerns not rodents but birds."; "There are differences in the composition of the social group [of certain birds] such as whether one or more sex provides help, and the stability of the associations between supernumeraries and the dominant breeders."

3. (Roman Catholicism) A married man or woman who is a secular member of Opus Dei, a Roman Catholic religious institution.Examples: "“Supernumeraries”, the bulk of Opus Dei members, can marry and live in their own homes, with slightly fewer spiritual obligations."