fence
篳 centers on a barrier made of bamboo or similar material: a fence or enclosure.
篳 combines 竹 (bamboo) with 畢, which likely contributes the sound and may relate to finishing or completing, suggesting a bamboo fence or enclosure.
The top 竹 is bamboo, and the bottom 畢 looks like a net or grid. Picture a bamboo fence woven like a net to enclose a space.
For ヒチ, imagine a fence so tightly woven that even a tiny hitch (ヒチ) in the bamboo can't get through: hitch -> ヒチ.
small double-reed wind instrument used in gagaku (made of bamboo, with 7 holes on top and 2 below)