Lag - The amount of time whereby a successor activity will be delayed with respect to a predecessor activity.

Lead - The amount of time whereby a successor activity can be advanced with respect to a predecessor activity.

Lead Time - The time between a customer request and the actual delivery.

Lessons Learned - The knowledge gained during a project, which shows how project events were addressed or should be addressed in the future, for the purpose of improving future performance.

Lessons Learned Register - A project document used to record knowledge gained during a project, phase or iteration so that it can be used to improve future performance for the team and the organization.

Life Cycle - See project life cycle

Log - A document used to record and describe or denote selected items identified during execution of a process or activity. Usually used with a modifier, such as issue, change, or assumption.