noun
letter of introduction
A formal letter written to introduce someone, often used in business or academic contexts.
新しい病院に行く前に、主治医に紹介状を書いてもらった。
Before going to the new hospital, I had my primary doctor write a letter of introduction.
就職活動
For my job search, I asked my professor for a letter of introduction.
Compound of 紹介 (introduction) and 状 (letter, document).