The term log, when used in reference to project management terminology, refers to the full and complete document that contains all of the items that are needed to properly historically record any and all events, happenings, and occurrences relative to the activity that occurred in the complete preparation, ultimate execution, of the series of processes or activities. Logs in the realm of project management can run a wide gamut as far as type. Each individual component of projects may require their own individual logs. The different types of logs can include issue logs, different types of quality control logs (that can be combined or segmented), control logs of varying types, defect logs (in some cases these may be referred to as error logs), and action logs. Logs are of fundamental importance and they may ultimately provide vital if and when the need arises for a careful and thorough auditing of the project after its completion.
This term is defined in the 3rd and the 4th edition of the PMBOK.