1. the action of becoming larger or more extensive
2. the action of spreading to cover a wider area
3. a detailed treatment or development of an idea or principle

Examples

• The company announced plans for expansion into new markets.
• The expansion of the universe continues billions of years after the Big Bang.
• Thermal expansion causes metal to grow when heated.
• The book includes an expansion of the author’s earlier theories.
• Urban expansion has led to the loss of farmland.
• The expansion of the school will add ten new classrooms.
• Economic expansion created thousands of new jobs.