Definition of actinism in English:

actinism

noun

  • See actinic

    • ‘Optical radiation may cause chemical changes in living or non-living materials: this property is called actinism and radiation capable of causing such changes is referred to as actinic radiation.’
    • ‘The author here suggests the introduction of a useful word, radiance, to express the light, radiant heat, and actinism of the sun, which are evidently modifications of the same form of energy.’
    • ‘The germination of seeds in the spring is dependent upon the variations in the amount of actinism or chemical influence of light and heat.’

Pronunciation:

actinism

/ˈaktɪˌnɪz(ə)m/