Ontolog Forum

COSMO Common Semantic Model

COSMO is an effort proposed and driven by PatCassidy. This Common Semantic Model (COSMO) is conceived as being made up of a lattice of ontologies which will serve as a set of basic logically-specified concepts (classes, relations, functions, instances) with which the meanings of all terms and concepts in domain ontologies can be specified. The most important function of the COSMO is to serve as a Foundation Ontology that has a sufficient inventory of fundamental concept representations so that it can support utilities to translate assertions of fundamentally different ontologies into the terminology and format of each other. The use of a common set of defining concepts will permit accurate interoperability of knowledge-based systems using the logical relations of their ontologies as the basis for reasoning in the system. The COSMO can also be used as the starting ontology for creation of more specialized domain ontologies.

The idea of collaboratively developing COSMO emerged around the UpperOntologySummit of 2006 (ref. the mention of that in the proposed summit mission).

The development of COSMO is fully open, and any comments or suggestions from any sources are welcome. After some discussion and input from members in 2006, the development of the COSMO has been continued primarily by Patrick Cassidy, the chairman of the COSMO Working Group. Most of the classes in the current COSMO have been taken from the OpenCyc OWL version 0.78, and from the SUMO. Other elements were taken from other ontologies or developed specifically for COSMO.

The COSMO ontology is intended to be a merged ontology, initially derived primarily from elements (Types [classes], relations, and Inference Rules) existing in the public ontologies OpenCyc ( The version used was 0.78b OWL version) and SUMO ( both SUMO and the MILO extension were used). Additional elements were adopted from the BFO ( and DOLCE ( ontologies. Other elements were added that were not in any of the starting ontologies. The interpretations of the elements adopted from the public ontologies were in some cases significantly different from that of the original ontologies, reflecting a different way of representing some of the basic categories. In such cases the basic intended meanings are still similar, though they will have somewhat different logical properties. The current version is in the OWL format, and does not contain any inference rules beyond those using the built-in structures of the OWL format, primarily subclass and subproperty relations and restrictions. The COSMO is intended to be available in both OWL and SKIF (or some other Common-Logic compliant) formats, but the SKIF version has not yet been prepared.

The current direction of development of the COSMO ontology is to expand it until it includes representations of all of the "defining vocabulary" words in the Longman Dictionary of Contemporary English (LDOCE). That list, expanded to include the morphological variants (plurals, past tense, adverbial forms, etc.) is available at:

When this supplementation is completed, the resulting COSMO ontology will be tested to determine if it can serve as a "conceptual defining vocabulary" (CDV), an ontology analogous in function to the linguistic defining vocabulary of the LDOCE. The goal is that such a base CDV will have a sufficiently complete inventory of basic concept representations to allow creating logical specifications of the meanings of terms in any field, without the need to add to the basic inventory of primitive concepts already in the COSMO. The secondary goal of keeping the basic foundation ontology as small as possible is intended to make it easier to learn and easier to use, making it more functional as a basis for semantic interoperability.

It is expected that, as new domains are represented using the COSMO, additional primitive concepts will be recognized as needed, and will be added to the COSMO. If it is only occasionally necessary to add such new primitives, and the ratio of new primitives to additional described domain concepts falls as new domains are defined, then the COSMO will be functioning as intended.

See also: