透

By extension: “to seep in,” “to leak,” “to reveal,” “to become transparent.”

Phono-semantic compound:

辵 (착, “to walk slowly; movement radical”) – provides the meaning (indicating motion or passing through)

秀 (수, “excellent”) – provides the sound

The original sense of 透 is “to pass completely through something.”

This includes:

- physical penetration

- movement from one side to the other

- something reaching its farthest extent

透 is highly productive in science, medicine, engineering, and design vocabulary.

Common & standard compounds:

透過 (투과) — penetration; transmission (of light, radiation, signals)

透過性 (투과성) — permeability; transmissibility

透視 (투시) — fluoroscopy; X-ray viewing; see-through inspection

透視圖 (투시도) — perspective drawing

透明 (투명) — transparency; clearness

透明性 (투명성) — transparency (figurative or literal)

Scientific / technical terms:

透光 (투광) — light transmission

透光率 (투광률) — light transmittance

透水 (투수) — water permeability

透水性 (투수성) — permeability to water

透析 (투석) — dialysis

透析液 (투석액) — dialysis solution

透膜 (투막) — permeable membrane

Figurative / abstract usage:

透徹 (투철) — penetrating; thorough; incisive

洞察透徹 (통찰투철) — deeply insightful; penetrating insight

透徹力 (투철력) — penetrating power (of thought or analysis)

Less common / literary:

透映 (투영) — projection; shining through

透氣 (투기) — ventilation; air permeability

Semantic contrast

透 — Passing through completely

通 — Passing freely or being connected

貫 — Piercing or threading through

滲 — Gradual seepage

In Modern Chinese, 透 is very common and has a wide range of meanings, including:

- “to penetrate, to go through” (투과하다);

- “to leak (information)” (비밀이 새다);

- “to be seen through, to be transparent” (비쳐 보이다);

- “thoroughly, completely” (철저히), as in 看透 (to see through something completely).

The reading 숙 (숙) (“놀랄 숙”) is historically attested but not used in words or idioms today.