整理

1. Origins, structure, and basic meaning

• Structure: 整理(せいり) means putting mixed material in order by sorting it and removing what is unnecessary.
• Basic usage: 整理する applies to physical papers as well as thoughts, reasons, and conclusions.

2. Common pitfalls and similar expressions

• A different focus from 整頓
  • 整頓(せいとん) focuses on arranging objects neatly so they are easy to find or use. 整理 also covers sorting and clarifying content, as in 考えを整理する.