What is critical path in Project Management?

The sequence of tasks with no slack.

The critical path of the project Managenebt is the time Management

the shortest time to complete the project and it is the longest duration path through a network of tasks&  the critical activities without any float time

Critical path includes the activities which are imperitive for timley completion of the project, its longest path calculated considering accumulating the duration of activities in sequence/series.

A path with the series of activites having zero or negative float or the longest path in terms of duration is called the critical path.

Sequence of tasks with the longest duration that must be completed in order for the project to be done.

in other words, lets say you manage a project to upgrade your accounting software with a new package, and within the different tasks in the plan (buying and setting up new HW, configuring the software for your company, training the staff on the new package,.....etc), you find in your MS project plan that migrating the data from the old software package, transforming it and loading it to the new package takes the longest duration of the project. then this is considered to be your critical path, because if this part of the project is delayed, it will delay the whole project, while other tasks like training have a buffer and can start late to a degree and still would not affect the planned end date of your project.

I hope it was clear.

it is the shortest duration to complete the project in a series of activities (pert-cpm) which the total float is zero.