Alumnae (plural of Alumna) is a Latin word indicating a group of former female students or female students who have graduated from a college or university. If the group is composed of male students only, or male and female students together, we need to use Alumni, the plural of Alumnus.
Alumnae is regularly used in English maintaining its original Latin meaning, only the pronunciation has changed.
Listen to the correct pronunciation of Alumnae in English