Semantics refers to the meaning of words or data. In the case of data, semantics refers to not just how data is labeled or structured, but what the data actually represents in the real world, and how different data elements are conceptually related. Terms: the nouns and verbs of the domain [[Controlled vocabulary]]: terms with definitions (also glossary) [[Taxonomy]]: hierarchy of terms [[Ontology]]: taxonomy + relationships [[Knowledge graph]]: ontology + data A thesaurus is a crosswalk between vocabularies.