"Light" can also have the meaning of "having given birth", as in the title of the novel by William Faulkner "Light in August".
I am editing the first definition, light as the stuff that we use for vision. Maybe someone can improve on my definition, which is longer than I would wish and perhaps too technical. I think it's important to
* avoid the incorrect definition of light as a 'medium' * avoid reference to "the Sun and other very hot sources" as heat is not required for producing light, and the mechanisms for producing light belong in an encyclopaedia, not a dictionary * include mention of ultraviolet and infrared light as it is misleading to exclude such (anomalous) common usage. Alkhowarizmi (talk) 07:04, 26 January 2017 (UTC)