fence
圌 centers on a fence or enclosure, likely a circular or rounded barrier. The given meanings point to a physical boundary used for containment.
圌 combines the enclosure 囗 with 耑, which may relate to a boundary or rounded shape. The exact historical development is uncertain, but it likely represents a fenced or enclosed area.
The outer 囗 is a fence or wall, and inside is 耑, which looks like a rounded mound with a top line. Picture a circular fence around a small hill: 圌 is a fence.
For セン, imagine a fence made of a thousand (千, せん) bamboo poles tied together: 千 -> セン, and the fence encloses the area.