What does it mean when a fraternity or sorority is secret letter?

Secret letter refers to the practice of some fraternities and sororities to use letters of the Greek alphabet as symbols or codes to represent themselves. These letters are often used as initials or abbreviations for the fraternity or sorority's name, and can be found on merchandise, flags, and other items associated with the organization.

The use of secret letters can be traced back to the early days of fraternities and sororities, when they were often underground organizations. The letters provided a way for members to identify themselves to each other without revealing their membership to outsiders. In some cases, the letters also had symbolic meanings related to the fraternity or sorority's values or history.

Today, the use of secret letters is less common than it once was, but it is still practiced by some fraternities and sororities. It can be seen as a way to maintain a sense of exclusivity and tradition within the organization.