A simple definition of an Outlook Task is that it is a personal or work-related job or assignment whose progress can be tracked to completion. It is an activity that may have a completion date and current status.
However, it is not quite as simple as that, as there are three types of Outlook Task and for each task there are three levels of priority and five stages of progress.
The three types of task that you can have in your Tasks folder, at any one time are:
A task created by you and assigned to someone else
A task created by someone else and assigned to you
A task created by you for your own benefit
Each type of task has a different icon but, even if you include the fields Requested By, Assigned, and Owner in the folder view, it is still not easy to distinguish, and therefore manage, the different types of task.
Each task can have priority settings of Low, Normal, or High and be at one of the following stages: Not Started, In Progress, Waiting on Someone Else, Deferred...