magic number

American  

noun

Physics.

1. the atomic number or neutron number of an exceptionally stable nuclide.

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magic number British  

noun

1. physics any of the numbers 2, 8, 20, 28, 50, 82, and 126. Nuclides with these numbers of nucleons appear to have greater stability than other nuclides

2. chem a number of atoms that is particularly stable in certain types of compound that have clusters of the same type of atom

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magic number Scientific  

/ măj′ĭk /

1. Any of the numbers, 2, 8, 20, 28, 50, 82, or 126, that represent the number of neutrons or protons in strongly bound and exceptionally stable atomic nuclei. The existence of such stable nuclei is explained by assuming a shell structure for nucleons, much like the shell structure of electron orbitals around the nucleus.

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Etymology

Origin of magic number

First recorded in 1945–50

Example Sentences

“The new ‘magic number’ reflects a convergence of factors — from persistent inflation and longer life expectancies, to uncertainty about the future of Social Security,” said John Roberts, chief field officer at Northwestern Mutual.

From MarketWatch

Our magic number is fluid and unique to each of us.

From The Wall Street Journal

In these cases, the well known magic numbers vanish, round nuclear shapes break down, and the nucleus can shift into a highly distorted form.

From Science Daily

There’s no “magic number” for marriage — there’s not even one for retirement — but financial stability is positively correlated with happy marriages.

From MarketWatch

"But with so much at stake and shareholders to appease, it seems ultimately the magic number couldn't be found, at least not right now," she added.

From Barron's

Related Words

• code
• confidential information
• key
• mystery