Where does “圦樋” come from?

圦樋 (Japanese) comes from Japanese 入り, from Japanese 入る, from Old Japanese いる.

Ancestry of “圦樋”, step by step

Step	Language	Word	Meaning
1	Japanese	入り	entering; entry, going in; entry, entering
2	Japanese	入る	to enter, go into, get into; to arrive; to join a...
3	Old Japanese	いる	—