As with physical items, a virtual item can also be broken down into component virtual items by creating horizontal relationships between virtual items, or between the parent virtual item and its components, to define a complete process or functional breakdown. This breakdown is called a Virtual Item Breakdown Structure. A virtual item breakdown structure can only be defined in the context of a Virtual Item Group.

See also COMPONENT, HORIZONTAL RELATIONSHIP, ITEM-ITEM RELATIONSHIPS, PARENT, PHYSICAL ITEM, VIRTUAL ITEM, and VIRTUAL ITEM GROUP.