How to say "expansion" in Japanese

• 拡大かくだいJLPT N3approx.Common
  noun, suru verb, transitive verb, intransitive verbCovers expansion as enlargement or widening in scale, scope, or size — a zoomed-in image, a growing business, spreading influence. Think of making something visibly or measurably bigger rather than adding parts to it.
  今年ことしは事業じぎょうが５０％拡大かくだいした。↗

  The business has expanded by 50% this year.
• 拡張かくちょうJLPT N2approx.Common
  noun, suru verb, transitive verbCovers expansion as extension: adding to capacity, facilities, or functionality. Typical of technical and engineering contexts — expanding memory, extending a system's features, enlarging plant or equipment.
  学校がっこうの体育館たいいくかんが拡張かくちょうされた。↗

  The school gymnasium was enlarged.
• 発展はってんJLPT N3approx.Common
  noun, suru verb, intransitive verbCovers expansion as growth and development — something progressing and flourishing over time, such as an economy, a city, a company, or relations between countries. Less about size added than about advancement.
  彼かれらは町まちの発展はってんに大おおいに貢献こうけんしてくれるだろう。↗

  They will contribute greatly to the growth of the town.
• 拡充かくじゅうJLPT N2approx.Common
  noun, suru verb, transitive verbCovers expansion as augmentation and enrichment — building up staffing, facilities, or services so they are fuller and stronger. It is the word when expansion means beefing up provision rather than physical size or spread.
  教育施設きょういくしせつを拡充かくじゅうする金かねをもっと多おおくと望のぞんでいる。↗

  People want more money to expand educational institutions.
• 膨張ぼうちょうJLPT N1approx.Common
  noun, suru verb, intransitive verbCovers physical expansion and swelling — of gases, of metals under heat, of the universe — and ballooning increase, as of budgets or armaments swelling beyond their proper size.
  多おおくの天文学てんもんがく者しゃは、宇宙うちゅうは永遠えいえんに膨張ぼうちょうしてゆくものだと考かんがえている。↗

  Many astronomers assume that the universe expands infinitely.

Use 拡大 for enlarging scale or scope, 拡張 for extending capacity or function, 発展 for growth and development, 拡充 for augmenting provision, and 膨張 for physical expansion or ballooning growth.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 拡大かくだいexpansion
• 拡張かくちょうexpansion
• 発展はってんdevelopment
• 拡充かくじゅうexpansion
• 膨張ぼうちょうexpansion
• 進出しんしゅつadvance (into a new market, industry, etc.)
• 伸長しんちょうexpansion
• 増設ぞうせつadding (equipment, facilities, etc.)
• 伸展しんてんexpansion
• エキスパンションexpansion
• 増成ぞうせいexpansion
• 展開式てんかいしきexpansion
• 拡張化かくちょうかenlargement
• 補訂ほていrevising (and supplementing)
• 拡張機能かくちょうきのうexpanded functionality
• 展延てんえんspreading out
• 膨化ぼうかswelling
• 展開てんかいexpansion
• 発達はったつexpansion (of a typhoon, low-pressure area, etc.)
• 膨大ぼうだいswelling