1. covering a large area; having great extent
2. comprehensive and detailed; thorough

Examples

• The fire caused extensive damage to the forest.
• She has extensive knowledge of European history.
• The company conducted extensive research before launching the product.
• The mansion sits on extensive grounds with beautiful gardens.
• The report includes extensive documentation of the findings.
• He traveled extensively throughout Asia during his gap year.
• The library has an extensive collection of rare books.