中身

1. Origins, structure, and basic meaning

• Structure: 中身, read なかみ, combines inside 中 with substance or body 身 to denote what is contained within.
• Basic usage: 箱の中身 means what is physically inside, while 議論の中身 means content or substance.

2. Common pitfalls and similar expressions

• Distinguishing meanings
  • It focuses on inner content in contrast with outward appearance 外見 or form 形式.