magic number

noun

Definition of magic number 

1 : one of a set of numbers for which an atomic nucleus exhibits a high degree of stability when either the proton or neutron count is equal to the number

2 : a number that represents a combination of wins for a leader (such as in a baseball pennant race) and losses for a contender which mathematically guarantees the leader's winning the championship

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First Known Use of magic number

1947, in the meaning defined at sense 2

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The first known use of magic number was in 1947

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