關

It is a phono-semantic compound made up of:

門 (문, “gate/door”) — providing the meaning (related to gates, closures);

𢇇 (관, “to tie, to fasten”) — providing the sound.

From meanings like “bar” and examples such as 관문 (關門, “checkpoint”) or 함곡관 (函谷關, a famous mountain pass), we see that 관 originally referred to a gate or barrier that separates inside and outside. As a result, many place names in the Chinese cultural sphere containing “관(關)” are linked to such gates or passes — for example, Kantō–Kansai (관동–관서) in Japan, or the Guanzhong (관중) region in China.

闗 (U+95D7)