Alignments are common in database interoperability projects and tasks however, from the perspective of the semantic web we are referring to ontology alignments when a variable degree of correspondence can be established between concepts that belong to different controlled vocabularies. It is in the nature of controlled vocabularies that a given concept from one vocabulary can have a level of correspondence with a concept in a different vocabulary, no matter if these controlled vocabularies comply with the same or with different ontologies.

There are different possible levels of correspondence between concepts from different controlled vocabularies. We refer to these as follows:

  • Has exact match
  • Has close match
  • Has broad match
  • Has narrow match
  • Has related match

There is a certain similarity between ontology alignments and semantic relationships however, while ontology alignments describe the proximity in the correspondence between two concepts from separate controlled vocabularies, semantic relationships are established between concepts of the same controlled vocabulary.

The following EuroVoc alignments are available for download: