圆
yuán · HSK 4
circle
⭕ 圆 = 囗 enclosure + 员 member; a closed boundary, hence round
The outer 囗 marks an enclosure or boundary; 员 (member, originally a round-mouthed vessel) gives the sound and hints at roundness. By extension 圆 covers complete, satisfactory, well-rounded outcomes.
圆 — enclosure 囗 + 員 (phonetic)
圆 is a phono-semantic compound. The outer 囗 (enclosure) suggests a round, closed shape, while 員 provides the sound and originally depicted a round-mouthed tripod vessel. Together they came to mean 'round' or 'circle,' later extending to 'complete' and the unit of currency.