Different calendar types require various methods to delete a calendar:
A synchronised Google calendar
To delete a Google calendar, you will need to open the → Calendars & task lists and click on the pencil icon. In the upper right corner you will see a recycle bin icon to delete this calendar. Please DO note, that by doing so, you will also delete this calendar from Google servers and there will be no way to retrieve this calendar once it is deleted. Furthermore, remember that you are not allowed (Google restrictions) to delete the main calendar and the read-only calendars. This is why you will not see the bin icon when trying to delete it.
Hint: Alternatively you can delete the calendar in Google Web Calendar and sync changes to BC 2.
A synchronised calendar from other sources (than Google)
To delete a synchronised calendar, you will have to access your online calendar. Search for the option to delete calendar and afterwards synchronise the changes to BC 2. Right after the sync the calendar will disappear from your BC 2.
A local calendar created in BC 2
You delete a local calendar similarly to Google synced ones. So open the → Calendars & task lists and click on the pencil icon. There you will find the bin icon to delete a local calendar. Please note, that the data from the whole calendar will be irretrievably gone.
Hint: If you are not able to delete a local calendar in BC ( i.e. there is no icon provided), please verify your stock calendar. Sometimes the calendars are added there per default and only there they can be deleted.