落とす

1. Origins, structure, and basic meaning

• Structure: 落とす is read as おとす and is a transitive verb for dropping an object or losing a possession by letting it fall.
• Basic usage: A physical drop appears in コップを床に落とす, while nearly losing an item appears in 定期券を落とすところだった.

2. Common pitfalls and similar expressions

• Difference from 落ちる
  • 落ちる is intransitive and presents something falling; 落とす is transitive and presents someone causing the fall.
• Drop and lose
  • Besides making an object fall, the verb can mean losing a possession after dropping it while out.