A number of people ask us to allow an colleague to view their diary in Outlook / Office 365.

The Way Microsoft Define the Term "Sharing Calendars" is a little ambiguous, though they do provide a great article on the subject.

If you want to allow someone to see your Free / Busy Time then your are looking at the Microsoft Version of Sharing.

If you want to allow someone to create / manage your Diary, it not sharing of a Calendar, but delegated access.

Either way, you will find the right method to do either in the Office 365 Platform here