being in excess of the usual, proper, or prescribed number; additional; extra. associated with a regular body or staff as an assistant or substitute in case of necessity. noun, plural su·per·nu·mer·ar·ies. a supernumerary or extra person or thing. a supernumerary official or employee.

Meaning of supernumerary in English supernumerary adjective formal us / ˌsuː.pɚˈnuː.mə.rer.i / uk / ˌsuː.pəˈnjuː.m ə r. ə r.i / in addition to the number usually needed: Supernumerary teeth often are found in the upper jaw just behind the front teeth.

su·per·nu·mer·ar·y (so͞o′pər-no͞o′mə-rĕr′ē, -nyo͞o′-) adj. 1. Exceeding a fixed, prescribed, or standard number; extra: a supernumerary rib. 2. Exceeding the required or desired number or amount; superfluous: an employee who became supernumerary after the merger. See Synonyms at superfluous.

supernumerary noun [ C ] formal uk / ˌsuː.pəˈnjuː.m ə r. ə r.i / us / ˌsuː.pɚˈnuː.mə.rer.i / an extra employee, actor, member of a society, etc.: They're supernumeraries, the people on an opera stage who neither speak nor sing, yet whose presence in the production is crucial.