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Wolf number

American  
[woolf, vawlf] / wʊlf, vɔlf /

noun

Astronomy.

  1. a number indicating the degree of sunspot activity on the sun as a factor of observer idiosyncrasies, the number of sunspot groups, and the number of individual sunspots.

Etymology

Origin of Wolf number

1975–80; after Rudolf Wolf (1816–93), Swiss astronomer

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.