Dictionary.com
Thesaurus.com

K-line

American  
[key-lahyn] / ˈkeɪˌlaɪn /

noun

Physics.
  1. one of a series of lines K-series in the x-ray spectrum of an atom corresponding to radiation K-radiation produced by the transition of an electron to the K-shell.


Etymology

Origin of K-line

First recorded in 1895–1900