The controlled vocabulary of a database is the official subject headings for the database. Controlled vocabulary will vary depending on the discipline. Even when the word is the same in multiple disciplines, context will vary. For example, "stress" means one thing to a psychologist (anxiety, depression) and something else entirely to an engineer (metal fatigue, weight load). The controlled vocabulary of the database will vary depending on the subjects the database covers.
And how do you find the controlled vocabulary?
- Look for a thesaurus (or a glossary, or a list of subject terms)
- Look at the metadata in the database records