1) A management technique for subdividing a total job into its Component elements, which then can be displayed in a manner to show the relationship of these Elements to each other and to the whole.
2) A product-oriented family tree, composed of hardware, software, services, and other work tasks, which results from project Engineering effort during the Development and production of a Defense Materiel Item, and which completely defines the project or program. A WBS displays and defines the product(s) to be developed or produced, and relates the elements of work to be accomplished to each other and to the end product