分子

• Reading: ぶんし
• Romaji: bunshi
• Kanji breakdown: 分 (bun) — part, divide, minute; 子 (shi) — child, small thing
• Pronunciation: /bɯɴ.ɕi/

Meaning

Molecule. The smallest unit of a chemical compound that retains its properties.

A noun used in chemistry and physics for the smallest particle of a substance that retains all the chemical properties of that substance. Consists of two or more atoms bonded together. Common collocations include 分子構造 (bunshi kouzou, molecular structure), 分子量 (bunshi ryou, molecular weight), and 水分子 (sui bunshi, water molecule). Note: 分子 also means 'numerator' in mathematics (the top number of a fraction).

Examples

1. 水の分子は二つの水素原子と一つの酸素原子からできている。 A water molecule is made up of two hydrogen atoms and one oxygen atom.
2. 温度が上がると分子の運動が激しくなる。 As temperature rises, the motion of molecules becomes more vigorous.
3. この技術で一つ一つの分子を観察できるようになった。 This technology has made it possible to observe individual molecules.

Usage Guide

Context: chemistry, physics, biology

Tone: neutral

Origin & History

From Sino-Japanese: 分 (bun, part/divide) + 子 (shi, child/small thing). Literally 'divided small thing' — the smallest divisible unit of a chemical substance. The term was coined in Japan during the Meiji era to translate the Western scientific concept.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal