PERT Chart Terminology
A task is an arrow-shaped element of a PERT chart, representing activity that must be performed.
A milestone is an element of a PERT chart, marking the completion of a task or several tasks.
A category is an additional meta-information used for positioning and grouping milestones and tasks.
A critical path is the longest possible continuous pathway taken from the initial event to the terminal event (some projects can have several critical paths). It determines the total duraton of the project, so any delay along the path means a delay for the whole project. The critical path is calculated by the Critical Path Method (CPM) – an algorithm for scheduling a set of project activities.