county in Henan, rising and dash
滎 is a rare kanji with two distinct meanings that do not share a single clear center: it names a county in Henan, and it describes water rising and dashing. The county name is a proper noun, while the water sense is a vivid natural image.
The exact historical development of 滎 is uncertain. It visually combines 水 (water) with a top element that resembles 火 over 冖, but the original component relationships are not clearly established.
The bottom 水 is water, and the top looks like fire 火 under a cover 冖. Picture water trapped under a hot lid, boiling and dashing upward—a vivid image for rising and dashing water. For the county name, imagine that same bubbling water marking the spot on a map.
For ケイ, picture a kettle (ケイ) of water boiling over: the kettle sound cues ケイ, and the water dashes up like the kanji's image.