湿度
しつど · shitsudo · JLPT N3 · noun
humidity
💧🌡️ 湿度 = damp (湿) + degree (度): the degree of dampness
湿 (shitsu) means damp or wet, as in 湿気 (shikke, moisture). 度 (do) means degree or measure, the same ending as 温度 (ondo, temperature) and 速度 (sokudo, speed). So 湿度 is literally the measured degree of wetness in the air.
湿 — water 氵 + 㬎 (phonetic, 'visible')
湿 originally depicted dampness, combining the water radical 氵 with 㬎, which suggests sun shining on silk threads being dried. The water component carries the meaning 'wet/damp,' while 㬎 hints at the pronunciation. Modern simplified form 湿 replaced traditional 濕.
度 — 广 (shelter) + 庶 abbreviated (phonetic)
Originally depicted a hand measuring length under a shelter, meaning 'to measure' or 'a measure/standard.' From this came extended senses like 'degree,' 'extent,' and 'to pass through' (as in passing time). The reading 'dù' means degree/measure, while 'duó' preserves the older verbal sense of measuring.