Difference between appointments, meetings & events
[Some of the following is taken from the Microsoft website]
An appointment is a block of time you mark on your calendar for a specific
activity, for example, a lunch appointment, or to set aside time to work on a
project. Appointments can be a single occurrence or can be scheduled to repeat,
for example, a weekly appointment to prepare a report. Your appointment may be with other people, but will appear only on your
If you want to share an appointment with other people in your organization so
that it appears on their calendars in addition to your own, you can Request a
A meeting is an appointment you share with another person. When you request a meeting, in addition to setting a time and subject, you'll add a list of attendees to invite. You can also add resources, such as a conference room or projector. If the recipients are in the shared address book, you'll be able to see their free/busy time. Most recipients will be able to respond to the meeting request by accepting, tentatively accepting, or declining your invitation. Like appointments, meeting requests can be for a single meeting or can be scheduled as repeating meetings.
See: create a meeting
All day events can be used when you want to show an activity
that occurs on a specific day, throughout the day.
For example, you might use an all day event to block out your Calendar as busy when you are on Annual Leave or at a conference, for example.