altLabels

altLabels are labels assigned to a knowledge-organization concept that are not the preferred label. They provide synonyms or additional terms that users may search for or encounter, helping to improve recall and accessibility in multilingual or multi-terminology catalogs.

In SKOS, the property skos:altLabel links a concept to a literal string representing an alternative label. Each value is usually language-tagged (for example, "car"@en). A concept can have multiple altLabel entries across languages.

Alt labels are labels only and do not imply a change of concept identity. They are not used to define semantic relationships between concepts; rather, they offer alternative textual expressions for display and search. Applications may use altLabel values to broaden query matches.

Best practices include avoiding duplication of the preferred label, tagging labels with appropriate language tags, and selecting alt labels that reflect common terminology used by intended users.

In practice, altLabels are widely used in thesauri, vocabularies, and catalogs to support user-friendly interfaces and effective search, especially in multilingual contexts.

See also SKOS, SKOS-XL.