In a batch execution system such as ISA-88, the MBOM will refer to the formula part of the recipe.
The "recipe procedure" explains the steps to make the end product.
The "equipment requirements" describes the machines and tools that are necessary to make the product.
[1] In ISA-95 terms, the MBOM will refer to the "material specification" in the "product definition model".
The MBOM typically contains more information than what is needed to do the MRP (material requirements planning) part of an MPS (master production schedule) in an ERP (enterprise resource planning) system.