凝固

• Reading: ぎょうこ
• Romaji: gyoko
• Kanji breakdown: 凝 (gyo) — to congeal, to concentrate; 固 (ko) — solid, hard
• Pronunciation: /ɡjoː.ko/

Meaning

Solidification; coagulation; the process of a liquid changing to a solid state, or of a substance clotting or hardening.

A phase-transition term in physics and chemistry: 凝固 refers to the liquid-to-solid transition (凝固点 — freezing/solidification point). In medicine and biology, 凝固 refers to coagulation (血液凝固 — blood coagulation). The solidification point is called 凝固点 (gyokoten), and depression of this point is 凝固点降下 (freezing point depression). The verb form is 凝固する. Contrasted with 融解 (melting, the reverse process).

Examples

1. 水は0℃で凝固し、氷になる。この温度を凝固点という。 Water solidifies at 0°C and becomes ice. This temperature is called the solidification point.
2. 血液凝固のメカニズムが正常に機能しないと、出血が止まりにくくなる。 When the blood coagulation mechanism does not function normally, bleeding becomes difficult to stop.
3. 溶融した金属が型に流し込まれ、冷却されることで凝固し、目的の形状になる。 Molten metal is poured into a mould and, upon cooling, solidifies into the desired shape.

Usage Guide

Context: physics, chemistry, medicine, materials science, metallurgy

Tone: technical, neutral

Origin & History

Sino-Japanese compound: 凝 (gyo) — to congeal, to concentrate + 固 (ko) — solid, hard. 凝 conveys the gathering and thickening of matter, as in 凝縮 (condensation). Adopted in Meiji-era Japan for scientific descriptions of phase transitions.

Cultural Context

Era: Meiji-Modern

Generation: Adult

Social background: Educated