sunrise
暹 centers on the moment the sun appears above the horizon: sunrise. It is a specific, visual event rather than a broad concept of light or day.
暹 combines 辶 (movement) with 日 (sun) and 隹 (a bird-like component), likely suggesting the sun moving upward like a bird taking flight at sunrise. The exact historical development is uncertain.
The sun 日 rises over a bird-like shape 隹 while the movement radical 辶 suggests motion. Picture the sun gliding upward like a bird at dawn: 暹 is sunrise.
For セン, imagine a thousand (千, せん) birds taking flight at sunrise: 千 -> セン, and the scene matches the sun rising over the bird component.
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