[ ˌsu:pə'nju:m(ə)r(ə)ri ]
■ adjective
1》 present in excess of the normal or requisite number.
2》 not belonging to a regular staff but engaged for extra work.
↘(of an actor) appearing on stage but not speaking.
■ noun ( plural supernumeraries ) a ~ person or thing.
Origin
C17: from late L. supernumerarius '(soldier) added to a legion after it is complete'.