BOM (bill of materials)
A BOM lists everything a product is made of: materials, components and sub-assemblies, with the quantity needed per unit. The structure is multi-level, because a sub-assembly has a bill of its own, and so does the one below it.
Every BOM line points to an item number in the master data, a unit of measure and a consumption standard. In metal shops and plastics processing that standard also covers offcuts and allowances, because a finished part does not come out of a steel sheet or a shot of resin on its own. Exploding the BOM for an order produces the list of what has to be issued from stock or bought.
The BOM describes material, the routing describes labour and machines. Only together do they form the product's process definition and the basis for costing, which sales uses to price an enquiry and accounting uses to calculate cost of production.
Versions cause the most trouble. The designer changes the product while orders released against the previous version are still in progress, so the BOM needs a revision number and an effective date. The same problem in another shape is a bill living in the designer's spreadsheet alongside a separate, lagging record in the ERP.
The signal that this concerns your company is rebuilding the material list from scratch for every enquiry, plus a repeating gap between what left the warehouse and what the system said would leave it.