M-line

[ em-lahyn ]
/ ˈɛmˌlaɪn /

noun Physics.

one of a series of lines (M-series) in the x-ray spectrum of an atom corresponding to radiation (M-radiation) caused by the transition of an electron to the M-shell.

Origin of M-line

First recorded in 1920–25

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019