密度

• Reading: みつど
• Romaji: mitsudo
• Kanji breakdown: 密 (mitsu) — dense, close, secret; 度 (do) — degree, extent, measure
• Pronunciation: /mi.tsɯ.do/

Meaning

Density. The degree of compactness of a substance, or how closely packed something is.

A noun used in physics for mass per unit volume, but also widely used figuratively to describe the concentration or intensity of things. 人口密度 (jinkou mitsudo, population density) is one of the most common collocations. Also appears in 密度が高い/低い (mitsudo ga takai/hikui, high/low density). Figuratively used to describe packed schedules or rich content — 密度の濃い時間 (mitsudo no koi jikan, time packed with meaningful activity).

Examples

1. 東京は世界でも人口密度が非常に高い都市だ。 Tokyo is a city with an extremely high population density even by world standards.
2. 鉄は水より密度が大きいので沈む。 Iron sinks because its density is greater than water.
3. 今回の研修は密度の濃い三日間だった。 This training program was a packed, content-rich three days.

Usage Guide

Context: physics, geography, everyday figurative use

Tone: neutral

Origin & History

From Sino-Japanese: 密 (mitsu, dense/close/secret) + 度 (do, degree/extent). Literally 'degree of denseness' — how tightly packed something is.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal