Translation guide
The English word "expansion" covers physical enlargement, business growth, and abstract extension. Japanese uses different words depending on what is expanding and how.
Something becomes larger in physical dimensions or volume.
General term for enlargement, magnification, or scaling up. Used for images, maps, scale, and physical size.
画像を拡大してください。
Please enlarge the image.
事業の拡大を計画している。
We are planning the expansion of our business.
Expansion due to internal pressure, like swelling, inflation, or thermal expansion. Often used for gases, balloons, or abstract things like budgets.
空気が熱で膨張する。
Air expands with heat.
予算が膨張している。
The budget is ballooning.
Elongation or stretching in one dimension. Used in technical contexts like material science.
ゴムの伸長率を測定する。
Measure the elongation rate of the rubber.
A company, market, or economy grows in scale, reach, or activity.
Same word as physical enlargement, but very common for business expansion (market share, operations, scale).
海外市場への拡大を目指す。
We aim for expansion into overseas markets.
Growth, often organic or developmental. Used for economic growth, company growth, or personal development.
Expansion in the sense of unfolding, developing, or rolling out new activities. Often used for business strategies or story development.
Something non-physical becomes broader or more inclusive.
Extension or expansion of functions, scope, or capabilities. Common in IT (memory expansion, browser extensions) and abstract domains.
機能を拡張するプラグイン。
A plugin that expands functionality.
概念の拡張について議論する。
Discuss the expansion of the concept.
Also used for abstract expansion like influence or power.
Elaborating or adding detail to something previously stated.
To explain in detail; to elaborate. This is the most natural way to say 'expand on an idea'.
その点について詳しく説明してください。
Please expand on that point.
To expound or elaborate in a formal, often written context. Literary and somewhat rare.
著者はその理論を敷衍している。
The author expands on that theory.
拡大 is for making something larger in scale or size (images, business). 拡張 is for extending capabilities or scope (software, concepts). 膨張 is for swelling or inflating (gas, budgets).
When talking about expanding functionality or a concept, 拡張 is more precise. Using 拡大 might sound like you're just making it bigger, not adding new parts.
その会社はアジアへの拡大を計画している。
The company plans an expansion into Asia.
熱は金属の膨張を引き起こす。
Heat causes the expansion of metals.
このソフトウェアはプラグインによる拡張が可能だ。
This software allows expansion via plugins.
経済の成長が続いている。
The economy continues to grow.
新規事業を展開する。
Expand into new business ventures.
影響力を拡大する。
Expand one's influence.