关节
guānjié · HSK 7
joint
🦴 关 (connect/close) + 节 (node, like a bamboo segment) = the connecting node = joint
节 is the same node-character used for bamboo segments, the natural bends in a stalk. Pair it with 关 (to link or close together) and you get 关节, the body's connecting node where two bones meet.
关 — door 门 + simplified 关 inside
关 is the simplified form of 關. The traditional character showed a gate (門) with a bolt or crossbar inside, depicting a barred door — hence 'to close' or 'shut'. Meaning later extended to 'pass' (a guarded gate), 'barrier', and figuratively 'concern' or 'connection'.
节 — bamboo radical 竹 (⺮) + 即
Originally written 節, depicting a bamboo joint — the segmented node where a stalk divides. The bamboo radical ⺮ gives the meaning, while 即 supplies the sound. From 'bamboo joint' the meaning expanded to any segment, hence 'section,' 'festival' (a marked point in the year), and 'restraint' (knowing where to stop).