Translation guide
The English word "diffusion" refers to the process of spreading something widely, whether it's physical particles, ideas, or cultural elements. In Japanese, different words are used depending on what is spreading and how.
Describing the scientific process where molecules move from high to low concentration, or the general physical spreading of substances.
The standard scientific term for diffusion in physics, chemistry, and biology. Also used metaphorically for the spread of information or rumors.
気体の拡散は温度に依存する。
The diffusion of gases depends on temperature.
インクが水中で拡散した。
The ink diffused in the water.
Intransitive verb meaning 'to be scattered' or 'to spread out'. Used for physical objects dispersing, not for scientific diffusion.
紙が床に散らばっている。
Papers are scattered on the floor.
Transitive verb meaning 'to scatter' or 'to disperse'. Used when someone or something causes scattering.
風が落ち葉を散らした。
The wind scattered the fallen leaves.
Describing how concepts, innovations, or cultural practices become widely adopted or known.
The most common term for the spread or popularization of technology, ideas, or practices. Implies becoming widely used or accepted.
スマートフォンの普及は急速に進んだ。
The diffusion of smartphones advanced rapidly.
この技術の普及には時間がかかるだろう。
The diffusion of this technology will take time.
Often used for the spread of culture, religion, or information. Can have a slightly academic or formal tone.
Also used metaphorically for the spread of information, especially on social media or in news. Often implies rapid, uncontrolled spread.
Intransitive verb meaning 'to spread' or 'to expand'. Very common and versatile, used for physical and abstract spreading.
Transitive verb meaning 'to spread' or 'to disseminate'. Used when someone actively spreads something.
Referring specifically to atomic or molecular diffusion in solids, liquids, or gases, often in academic or engineering contexts.
The standard technical term. Used in compound words like 拡散係数 (diffusion coefficient).
拡散係数を測定する。
Measure the diffusion coefficient.
Describing the spread of cultural items—such as ideas, styles, religions, technologies, languages—between individuals, whether within a single culture or from one culture to another.
The specific term for cultural diffusion in academic contexts.
文化伝播の研究は人類学の重要な分野だ。
The study of cultural diffusion is an important field in anthropology.
Can be used alone to imply cultural diffusion, but often combined with 文化 for clarity.
文化の伝播は時に摩擦を生む。
Cultural diffusion sometimes causes friction.
拡散 (kakusan) is the most general term for diffusion, covering physical, chemical, and metaphorical spreading. 普及 (fukyū) specifically implies popularization or widespread adoption, often of technology or ideas. 伝播 (denpa) is used for the transmission or propagation of culture, religion, or information, often over distances or time.
The English word 'diffusion' is often translated directly as 拡散, but in many contexts, especially for the spread of ideas or technology, 普及 or 広がる is more natural. Using 拡散 for everything can sound overly scientific or unnatural.
The diffusion of Buddhism occurred via the Silk Road.
誤情報がSNSで拡散された。
Misinformation was diffused on social media.
その噂はすぐに広がった。
The rumor diffused quickly.
彼は新しい教育法を広めた。
He diffused a new teaching method.