mediate · intervene

1. Origins, structure, and basic meaning

• Structure: 介 relates to entering between or connecting things and is read かい in 紹介, 介入, and 介護.
• Basic usage: 紹介 means introduction or referral, 介入 means intervention, and 介護 means care for someone who needs assistance.

2. Common pitfalls and similar expressions

• What is introduced and to whom
  • In 友人に歯医者を紹介する, に marks the friend receiving the referral, and を marks the dentist being recommended.
  • 紹介してもらう describes receiving an introduction or referral rather than providing one.
• Evaluating intervention
  • 介入, read かいにゅう, means a third party becoming involved in a matter.
  • It can help settle a dispute or amount to excessive interference, so the word alone does not always carry a positive or negative judgment.