方舟

1. Origins, structure, and basic meaning

• Structure: 方舟(はこぶね) is a noun meaning an ark.
• Basic usage: It is used for a vessel serving as a refuge in legends or stories.

2. Common pitfalls and similar expressions

• Not just any vessel
  • Unlike 船, a broad word for a vessel, 方舟 refers specifically to the concept of an ark.