/ ˌsuːpəˈnjuːmərəri; ˌsjuː-; NAmE ˌsuːpərˈnuːməreri/ adjective
( formal ) more than you normally need; extra
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WORD ORIGIN
early 17th cent.: from late Latin supernumerarius (soldier) added to a legion after it is complete, from Latin super numerum beyond the number.