When doing your Setup of your Calendar, here is the different categories of day / Day types:

Normal: students are expected to attend school today.

Holiday: a statutory holiday.

Special: professional activity/development day where students do not attend school.

Board Holiday: a non-school day affecting all schools in the board such as March/Spring Break.

Grant: an unexpected closure such as weather or no heat in the school.

Exam: (secondary schools only) exam day for the whole school. Regular period class attendance is disabled for these dates, however exam day attendance is available to record am/pm attendance.