'Illuminant' definitions:

Definition of 'illuminant'

From: WordNet
noun
Something that can serve as a source of light

Definition of 'Illuminant'

From: GCIDE
  • Illuminant \Il*lu"mi*nant\, n. [L. illuminans, -antis, p. pr. of illuminare.] That which illuminates or affords light; as, gas and petroleum are illuminants. --Boyle. [1913 Webster]

Synonyms of 'illuminant'

From: Moby Thesaurus