magic number

noun

Physics.

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

magic number

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

magic number

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.

Word History and Origins

Origin of magic number¹

First recorded in 1945–50

Example Sentences

In a 5-4 extra-innings win over the Arizona Diamondbacks that lowered their magic number to clinch the National League West to one, the Dodgers again squandered a late-game lead when their traditional relievers faltered.

From Los Angeles Times

Their magic number for clinching an 11th division title in 12 seasons is 10 with less than two weeks left in the regular season.

From Los Angeles Times

When asked if he would repeat the drinks after Friday's round, he replied: "Be rude not to. I think three's the magic number."

From BBC

Easily attaining the top-25 finish that took her to the magic number of 20 eligibility points, meant that she would avoid potential golfing torture at qualifying school for the primary women's tour.

From BBC

The magic number shows up on smartwatches, fitness apps and office step challenges.

From Los Angeles Times

Related Words

• code 
• confidential information www.thesaurus.com
• key 
• mystery