Semantic interoperability means the capability of different information systems to communicate information consistent with the intended meaning. In more detail, the intended meaning encompasses
1. the data structure elements involved,
2. the terminology appearing as data and
3. the identifiers used in the data for factual items such as places, people, objects etc.
Obviously communication about data structure must be resolved first. In this case consistent communication means that data can be transferred between data structure elements with the same intended meaning or that data from elements with the same intended meaning can be merged. In practice, the different levels of generalization in different systems do not allow the achievement of this ideal. Therefore semantic interoperability is regarded as achieved if elements can be found that provide a reasonably close generalization for the transfer or merge. This problem is being studied theoretically as the query containment problem. The CRM is only concerned with semantic interoperability on the level of data structure elements.