真空
zhēn kōng · HSK 7
vacuum
🪐 真 true + 空 empty = a true emptiness, i.e. a vacuum with nothing in it
真 (zhēn) means true or real and 空 (kōng) means empty. A vacuum is literally a true emptiness: space with all the air pumped out. 空 also means sky, the wide empty expanse overhead.
真 — 匕 (spoon) over 目 (eye) over 八 (eight/base)
真 originally depicted a person or vessel used in ritual, conveying the idea of something genuine or true. Over time the form was reanalyzed as components like 匕, 目, and a base, but the core meaning of 'real, true, genuine' has remained stable since early bronze inscriptions.
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.'