In project management, a critical path is the sequence of project network terminal elements with the shortest overall duration.
The duration of the critical path determines the duration of the entire project. Any delay of a terminal element on the critical path directly impacts the planned project completion date (i.e. there is no slack on the critical path).
A project can have several critical pahts. A path just shorter of the critical path is called a sub-critical path.
The critical path method was invented by the DuPont corporation.