bright
熲 centers on brightness or radiance, often associated with light or fire.
熲 combines 火 (fire) with 頃 (which likely contributes the sound), suggesting brightness from fire. The exact historical development is uncertain.
Fire 火 on the left and a head-like shape 頁 on the right: imagine a bright flame illuminating someone's face, making everything bright.
For ケイ, picture a bright flame shaped like the letter K: K -> ケイ, and the fire glows brightly.