sunshine
昤 centers on bright, clear sunlight: sunshine itself, or the quality of being sunlit.
昤 combines 日 (sun) with 令, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to sunlight.
The sun 日 on the left shines on the right side 令, like a command of light: 昤 is sunshine.
For レイ, imagine a ray of sunshine: ray -> レイ, and the sun 日 makes the ray bright.
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