In Jain context, the daylight or light of day is simply the radiance of the Sun, i.e. Surya, and the light is described as “jyoti” (light) or “prabha” (radiance). If you were asking about a specific Jain hymn, mantra, or sutra that uses a phrase like “the light of day,” please tell me the exact text or commentaries you have in mind, and I can explain its Jain interpretation and usage.