環
カン, わ, たま, たまき

ring, circle, link, wheel

JLPT1 G7 S17 F409

睘# was originally 袁 (wrap about/enclose) + 目 eye → all-encompassing observation (compare 觀). In derivative characters, the "all-encompassing" aspect of 睘 takes the aspect "circularity." 環 adds 玉 jewel → jeweled *ring*/bracelet → *circle*; *surround*. *Return* is a borrowed meaning via 還. For "ring," compare 鐶; for "bracelet," compare 釧.

[Full Kanji Etymology List]