Definition of illuminant in English:

illuminant

noun

technical
  • A means of lighting or source of light.

    ‘until 1880, oil was the only illuminant in use’
    • ‘When refined into kerosene, it was the only ‘cheap illuminant that burned in a bright, clean, safe manner,’ by far better than blubber and lard.’
    • ‘While in defensive situations illuminants can be most valuable, in offensive situations, their use for surveillance and target acquisition can be counter-productive.’
    • ‘Also, only in the underwater optical environment do the illuminant and background change independently of each other, creating complex problems for crypsis.’
    • ‘Yes, there was a market for the refined illuminant.’
    • ‘However, because the background radiance in the pelagic environment is a complex result of multiple scattering and absorption events, its spectrum changes independently of the illuminant.’
    lamp, light, flashlight, beacon
    View synonyms

adjective

  • Giving off light.

    • ‘The XM930 contains a standard illuminant mix which provides approximately 1 million candlepower of light whereas the XM983 contains an infrared illuminant mix for use with standard night vision devices.’
    • ‘Given the illuminant spectrum and the spectral sensitivity functions for the camera, we can calculate the estimates of the weights at each pixel from six sensor outputs.’
    • ‘The owner of the illuminant system was Mr WK Hardacre, of Hellifield House.’
    • ‘Lexx casts an illumination spell so that they can all better see and they continue on with the glowing illuminant orb leading them.’

Origin

Mid 17th century: from Latin illuminant- illuminating from the verb illuminare (see illuminate).

Pronunciation

illuminant

/iˈlo͞omənənt/