expand

1. Origins, structure, and basic meaning

• Structure: 拡 has 8 strokes and the on-reading かく. 拡大 (かくだい) and 拡張 (かくちょう) concern increasing size or scope.
• Basic usage: 拡大 can describe enlarging a photograph or damage spreading; 拡張 can describe expanding a facility or the range of uses of software.

2. Common pitfalls and similar expressions

• What expands and preventing further spread
  • 写真を拡大して describes making a photograph larger. 被害の拡大を防ぐため states the purpose of preventing damage from spreading further.
  • 駐車場を拡張した means expanded a parking lot. ソフトの用途が拡張される passively describes new features broadening the ways software can be used.