snout, pig's head radical (no. 58)
彐 centers on the snout of a pig, used as a radical in characters related to pigs or snout-like shapes. Its standalone meaning is limited to this radical sense.
彐 is a pictograph of a pig's snout, stylized into a simple three-stroke form. It serves as a radical in characters related to pigs or snout-like shapes.
The three strokes form a boxy shape with a protruding top line, like a pig's snout seen from the front. Think of it as the snout radical.
For ケイ, imagine a pig named Kay sticking its snout out: Kay -> ケイ, and the snout is the radical 彐.