The ability to expand users' search queries using authority files was added in the April 2020 release of WorldCat Discovery. This allows users to discover relevant search terms to expand their search and perform a more effective search.
Our initial testing revealed that the LCNAF Library of Congress Name Authority File found matches in ways that users were unlikely to have meant their searches and we recommend leaving that one turned off.
Search Settings > Search Expansion Settings
✔ Expand users' queries using authority data
✔ Expand query using authority data by default
✔ AAT Art & Architecture Thesaurus
✔ LCGenre Library of Congress Genres
✔ LCSH Library of Congress Subject Headings
✔ MeSH Medical Subject Headings
Make sure to scroll down past the language options to hit the save button.