膠質

• Reading: こうしつ
• Romaji: koshitsu
• Kanji breakdown: 膠 (ko) — glue, gelatine; 質 (shitsu) — substance, quality
• Pronunciation: /koː.ɕi.tsɯ/

Meaning

Colloid; a colloidal substance. A mixture in which microscopically dispersed insoluble particles are suspended throughout another substance.

A specialised chemistry and materials science term. Colloids (膠質) differ from true solutions (真の溶液) in that the dispersed particles (1–1000 nm) do not settle by gravity. Examples include milk (牛乳), fog (霧), smoke (煙), and gelatin (ゼラチン). 膠質化学 (colloid chemistry) is important in pharmacy (薬学), food science, and materials science. The Tyndall effect (チンダル現象) — scattering of light in colloids — is a diagnostic test for colloidal systems. Also written as コロイド using the loanword from 'colloid'.

Examples

1. 牛乳は脂肪球がタンパク質に包まれた状態で分散している膠質の一例だ。 Milk is an example of a colloid in which fat globules are dispersed wrapped in protein.
2. 膠質粒子は光を散乱するため、コロイド溶液はチンダル現象によって白く見える。 Because colloidal particles scatter light, colloidal solutions appear white due to the Tyndall effect.
3. 医薬品の製剤設計では、薬剤を膠質粒子として分散させる技術が活用されている。 In pharmaceutical formulation design, technology for dispersing drugs as colloidal particles is utilised.

Usage Guide

Context: chemistry, materials science, pharmacy, food science, physics

Tone: technical, academic

Origin & History

Meiji-era Sino-Japanese translation: 膠 (ko) — glue, gelatine + 質 (shitsu) — substance, quality. 膠 refers to animal glue or paste, chosen because many colloidal substances (like gelatin and gum) are sticky and glue-like. The term translates the Greek-derived 'colloid' (kolla = glue + eidos = form).

Cultural Context

Era: Meiji-Modern

Generation: Adult

Social background: Educated