term

in X-ray spectroscopy
A set of levels which have the same electron configuration and the same value of the quantum numbers for total spin S and total orbital angular momentumL.
Source:
PAC, 1991, 63, 735 (Nomenclature, symbols, units and their usage in spectrochemical analysis - VIII. Nomenclature system for X-ray spectroscopy (Recommendations 1991)) on page 737