noun
bright sunshine; broad daylight
Often used in the phrase 白日のもとに (in broad daylight, publicly). Can also refer to the bright sun itself.
彼の悪事が白日のもとにさらされた。
His misdeeds were exposed in broad daylight.
白日のもとで見ると、その絵は色あせていた。
When seen in bright sunshine, the painting looked faded.