司空见惯
sī kōng jiàn guàn · HSK 7
a common occurrence (idiom)
司 Sikong (a court title) + 空 + 见 see + 惯 accustomed: an official so senior he's seen it all
From a Tang poem: the high official Sikong had seen so much luxury that nothing surprised him. So 司空见惯 means something so frequent it feels routine. 见 = see, 惯 = be used to.
空 — cave radical 穴 + 工 (phonetic)
Originally a phono-semantic compound: 穴 (cave, hole) gives the meaning of emptiness or hollow space, while 工 supplies the sound. The earliest sense was 'hole' or 'cavity,' which extended to 'empty,' 'sky,' and 'in vain.' The reading kòng (4th tone) specifically means 'free time' or 'vacancy.'
见 — eye 目 over legs 儿 (人)
见 (traditional 見) is a pictograph of a person 儿 with a large eye 目 on top, emphasizing the act of seeing. The original meaning 'to see' broadened over time to include 'to meet,' 'to perceive,' and 'view/opinion.' The simplified form 见 keeps the same structure in cursive shorthand.
惯 — heart radical 忄 + 贯 (guàn, string of coins)
A semantic-phonetic compound. The heart radical 忄 signals a mental or emotional quality, while 贯 — originally a string threading coins together — supplies the sound and the idea of 'threading through' continuously. Together they suggest a habit: something the heart strings together repeatedly until it becomes routine.