Definición y Significado de "subject line"

What is a "subject line"?

A subject line is the brief title or heading of an email that summarizes its main topic or purpose. It appears at the top of the message and helps the recipient understand the content of the email before opening it. A clear and relevant subject line can make it easier for recipients to prioritize or organize their emails. It is important for the subject line to be concise and direct to attract the recipient's attention and convey the message's key point.