If it is a business meeting then the following terms apply:
Attended: Attendees There were 12 attendees
Advised absences: Apologies There were three apologies
Unadvised absence: These are not usually mentioned in the minutes of business meetings however if you need a term then perhaps Absentees might be suitable although this could also include the people who sent their apologies There were 5 absentees including three apologies
If it is a business seminar, conference, workshop or training session then use Expressions of Interest (EOI) for those who have expressed an interest but not yet paid/confirmed and Registrations for those who have paid/confirmed. We have 10 registrations and 22 EOI�s. Once the event has occurred then use the word participants. We had fifty participants.
If it is an event such as a wedding reception, birthday party etc then people who RSVP are referred to as acceptances and inabilities. We can buy acceptance and inability cards to RSVP for such an event. We have received 30 acceptances and 12 inabilities.
See Wedding Acceptance & Wedding Inability cards by Hallmark
here
