Many traditional academic databases are put together by organizations that actually pay people (indexers) to review each item placed in the database and then assign to each item a few descriptive subject terms to characterize the topics discussed in the item. The subject terms the indexers apply are taken from a subject thesaurus that these database producers develop over time.
When searching traditional academic databases, start your search with the language that you know to describe your topic. Review the first few items on the result list that seem to be 'on topic.' In particular, look in the subject field of the item records to find the 'official' database thesaurus terms that are used to describe your subject. Then, rerun your search again using both your original terms as well as the thesaurus terms you found in the relevant records. You do not have to be constantly on the alert for variant vocabulary to express your subject.