跡

1. Origins, structure, and basic meaning

• Structure: 跡 is read as あと and is a noun for a trace, mark, or site left after something has passed or an event has occurred.
• Basic usage: A remaining mark appears in 足の跡が残る, while a former site appears in 火事の跡.

2. Common pitfalls and similar expressions

• Trace and site
  • It can denote a visible track or the place left by an earlier event such as a fire.
• Homophone 後
  • 後 means after or behind in time or position, while 跡 focuses on a remaining mark or former site.