square jewel, corner, angle, edge
圭 centers on a pointed, angular shape: a square jewel with a pointed tip, and by extension a corner, angle, or edge. The meanings all share the idea of a sharp, defined geometric form.
圭 is a pictograph of a pointed jade tablet, historically used as a ceremonial object. The modern form stacks two 土 shapes, but the original image was a tall, pointed jewel.
Picture two stacked blocks of earth (土) carved into a sharp, angular jewel. The pointed top and squared base make a corner or edge, like a gemstone cut into a precise angle.
For ケイ, imagine a jeweler carefully shaping a square jewel and saying 'K' for the sharp corner: K -> ケイ, and the jewel's edge is perfectly angled.
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medicine; art of medicine; doctor
doctor
ritual jades worn by feudal lords in ancient China
rough edges (of one's character, words, etc.); abrasiveness; harshness; sharpness
genital warts; venereal warts; anal warts; condylomata acuminata
genital warts; venereal warts; anal warts; condylomata acuminata