What role do synonyms play in keyword expansion?

• A. They Replace The Original Term
• B. They Are Used To Filter Documents
• C. They Are Ignored
• D. They Are Included Among Highly Correlated Terms

Answer: (D)

Synonyms in keyword expansion broaden the search by bringing in related terms that express the same concept. In practice, these terms are chosen because they tend to be highly correlated with the original term—their usage appears in similar contexts and documents about the same idea. Including synonyms as highly correlated terms lets the system retrieve more relevant results that might use different wording but refer to the same concept, increasing recall and coverage. They aren’t meant to replace the original term or to filter results; instead, they expand the query to capture linguistic variations. Some synonyms aren’t perfect matches in every context, but when treated as highly correlated terms, they share enough semantic and contextual similarity to improve search effectiveness.