Indexing – “intellectual analysis of the subject matter of a document (2.15) to identify the concepts (2.11) represented in it, and allocation of the corresponding index terms (2.26) to allow the information to be retrieved” (ISO 2011, 5)
The process of creating surrogate records, especially the access points for information packages; such work done in commercial enterprises is often called indexing, while similar work done in not-for-profit agencies is usually called cataloging (Taylor 1999, 244).
Indexing: Concepts and theory – (Hjørland 2018)
IEKO: https://www.isko.org/cyclo/indexing