世界

1. Origins, structure, and basic meaning

• Structure: 世界 (せかい) is a noun for the wider real world or a world established inside a story.
• Basic usage: 広い世界を見る expresses a wish to experience the real world; 動物だけが暮らす世界 names a fictional setting.

2. Common pitfalls and similar expressions

• Real world and fictional setting
  • Travel and personal experience select the real-world sense, whereas a story with special inhabitants selects an imagined world.