Some Greek terminology for you.
Active: fully-initiated member of a fraternity or sorority.
Alumnus (plural: alumni/alumnae): member of a fraternity or sorority who has graduated.
Bid: formal invitation to membership from a fraternity or sorority to a prospective member.
Brother: term used by initiated members in a fraternity when referring to each other.
Sister: term used by initiated members in a sorority when referring to each other.
Fraternity/Sorority: group of individuals bound together by common goals and rituals.
Greek: member of a fraternity or sorority.
Independent: person who is not a member of a fraternity or sorority.
Initiation: traditional ritual which brings the pledge into full membership in the chapter.
Interfraternity Council (IFC): representative governing body of all fraternities on campus. All NIC fraternities choose to participate in the Council.
Panhellenic Council (PHC): representative governing body of all sororities on campus. All NPC sororities choose to participate in the Council.
Legacy: prospective member of a fraternity or sorority who is the son, brother, daughter, sister, or other relative of a member of the fraternity or sorority.
Pin: the member pin is worn on the chest designating an initiate of a fraternity or sorority.
New Member/Associate Member: trial member of a fraternity or sorority who is working to become an initiate.
Recruitment: the activity by which fraternities and sororities seek new members.