For Men:
- singular: Alumnus
- plural: Alumni
For Women:
- singular: Alumna
- plural: Alumnae
For Groups, involving men and women:
If you follow the Latin rules, you can have a crowd of 499 women and 1 man, and the correct word is alumni. At the time the language was structured, men took precedence over women because of the perceived strength of masculinity. Personally, I don’t take offense, after all, it is proper grammar.