The IOF-s mission is to create a suite of ontologies intended to support digital manufacturing by facilitating cross-system integration both within the factory and across an enterprise, in commerce between suppliers, manufacturers, customers and other trading partners, and throughout the various stages of the product life cycle. The IOF Core Ontology resides at the top of this suite from an architectural perspective and contains terms found in a number of operational areas of manufacturing. These common terms appear, or are anticipated to appear, in two or more of the ontologies of the suite. Additionally, as the architectural approach chosen by the IOF is to base all of its ontologies on a single foundational or top-level ontology - for which the IOF chose the Basic Formal Ontology or BFO - the Core Ontology contains a number of intermediate-level terms that derive from BFO and from which common industry terms are in turn derived. Such intermediate-level terms are most often domain independent - meaning they are found in other industries and domains, such as in the banking, insurance, and healthcare industries, or in the sciences, as in the physics, chemistry and biology domains. The IOF Core Ontology is developed and formalized as an ontology using both first-order logic and version 2 of the Web Ontology Language (OWL). The use of logic ensures that each term is defined in a way that is unambiguous to humans and can be processed by computers. All terms appearing in the ontology are reviewed and curated by a working group and consensus is reached by validating usage in the context of manufacturing domain use cases.