Magns
Magns is not a term with a single, established meaning in major reference works. In published materials, magns tends to appear as an informal plural, a typographical variant, or a shorthand whose meaning depends on context. There is no universally recognized unit, quantity, or entity officially named magns.
Possible interpretations include: a misspelling or shorthand for magnons, the quasiparticles that arise from collective spin
When you encounter magns in a document, check whether the author defines the term, look for capitalization
Related terms include magnitudes, magnitude, magnification, and magnons.