Multiple databases on STNext provide online thesauri for one or more search fields including indexing terms. The CA Lexicon is the thesaurus for the Controlled Terminology (CT) field for the CAplus database. Controlled Terms cover key terminology added to CAplus records by CAS indexers and provide insight into the concepts covered in the original document. Controlled terms provide consistent terminology to help create comprehensive search strategies through the addition of synonyms and related terms or provide precise narrower terms to focus a search. Learn how to use online commands or the ease-of-use functionality built into STNext to find additional terms to expand search retrieval or narrow the focus. This e-seminar shows how to identify available thesauri and relationship codes for a database, options available to view the hierarchy of terms and how best to use online thesauri to improve your search results.