屋外

1. Origins, structure, and basic meaning

• Structure: 屋外 is read as おくがい and is a location noun used attributively in 屋外の催し and as the place of an action in 屋外で使う.
• Basic usage: It refers to events held outside or tools intended for use outside a building.

2. Common pitfalls and similar expressions

• Particle choice
  • Use の before a noun and で to mark where an action takes place.
• English form
  • Translate it as attributive outdoor before a noun or adverbial outdoors when it names the location.