伸缩
shēn suō · HSK 7
to lengthen and shorten
🔭🪜 伸 (stretch out) + 缩 (shrink back) = lengthen-and-shorten, hence retractable
伸 means to extend or stretch out; 缩 means to contract or pull back. Together they name the in-and-out motion of anything adjustable, like a telescope tube or an extendable ladder that slides longer and shorter.
伸 — person radical 亻 + 申 (extend/state)
伸 is a semantic-phonetic compound. The left side 亻 (person) gives the meaning, suggesting a body action, while 申 originally depicted lightning stretching across the sky and supplies the sound. Together they convey the idea of a person stretching or extending.
缩 — silk radical 糹 + 宿 (lodge, phonetic)
A semantic-phonetic compound. The silk radical 糹 carries the meaning, since shrinking and tightening were associated with drawing in cords or fabric. The right side 宿 (sù) supplies the sound. The original sense of binding cloth tight extended to the modern meaning 'to shrink' or 'contract.'