The term late start date, in terms pf project management, refers specifically to a specific point of time that takes place as part of the Critical Path Method. The particular point in time can specifically be designated as the latest point that could possible occur at which the designated schedule work activity in question can and may be initiated based on the previously determined network schedule logic, the project completion date that has already been discussed and determined, and any predetermined constraints or limitations that the project team has determined may exist in relation to the project. This date represents the latest point at which the activity may be kicked off without committing a violation in the previously dictated schedule constraints or without casing delays in the project completion date. The determination of the late start date takes place through the calculation of the backward pass of the project schedule network in question.
This term is defined in the 3rd and the 4th edition of the PMBOK.