What is the name of the letter section that indicates the subject matter being discussed?

The correct answer is the reference line, which serves an important purpose in correspondence. This section is typically found near the top of a letter and clearly indicates the subject matter being discussed. It helps the recipient quickly understand the context of the letter and what specific issues or topics will be addressed. Including a reference line aids in organization, especially in professional and legal communications, where clarity and immediacy are critical.

While the subject line might sound similar, it is not commonly used in traditional letter formats, especially in formal letters. The salutation is the greeting at the beginning of the letter, and the body is where the main content of the letter is presented. Therefore, the reference line is the most appropriate response to identify the section that specifies the subject matter.