研究所
yánjiùsuǒ · HSK 5
institute
🎓🔬 研 grind/research + 究 investigate + 所 place = place for deep research
研 (grind, study) + 究 (investigate thoroughly) together mean research; 所 marks a place or institution. So 研究所 literally names the place where deep investigation happens — a research institute or graduate school.
所 — door 戶 (left) + axe 斤 (right)
Originally a sound: an axe (斤) chopping wood near a door (戶), with 戶 also hinting at the pronunciation. Over time it was borrowed to mean 'place' or 'location,' and later became a grammatical particle nominalizing verbs ('that which…'). The concrete 'chopping' sense faded entirely.