Non-attendance is when you do not go to a place or event that you were supposed to go to. Schools, offices, and courts use it: a student’s non-attendance, non-attendance at a meeting, non-attendance at a hearing. It is a formal, slightly cold word — the kind you see on a letter, a report, or a school record. In everyday talk, people just say “didn’t go” or “was absent.” Though actually, the word does not by itself say why you stayed away. You might be ill, you might have forgotten, or you might have chosen not to come; it only names the fact that you were not there.