Work breakdown structure is the decomposition of the project into smaller and more manageable parts with each part satisfying the following criteria:

• Each WBS unit has a clear outcome.
• The outcome has a direct relationship to achieve the overall project goal.
• Each point has single point of accountability.

• Defines tasks to be performed, and their amendments
• Documents ownership for tasks
• Documents critical dependencies between tasks
• Documents inputs and output work products
• Documents the critical dependencies between defined work products
NOTE: A work breakdown structure may be integrated into/part of the schedule, see 14-06

Source as well Automotive SPICE®