Search Result for "line spectrum":
Wordnet 3.0

NOUN (1)

1. a spectrum in which energy is concentrated at particular wavelengths; produced by excited atoms and ions as they fall back to a lower energy level; 



WordNet (r) 3.0 (2006):

line spectrum
    n 1: a spectrum in which energy is concentrated at particular
         wavelengths; produced by excited atoms and ions as they
         fall back to a lower energy level