n.
Pronunciation: ˌ lü-m ə - ' nä-s ə -t ē
Function: noun
Inflected Form: plural -ties
Date: 1634
1 a : the quality or state of being luminous b : something luminous
2 a : the relative quantity of light b : relative brightness of something
3 : the relative quantity of radiation emitted by a celestial source (as a star)