Industrialization: The process of developing industries on a large scale, leading to increased production and economic growth. As industrialization expanded in late-19th-century America, it created new job opportunities and helped shape the middle class.
Labor unions: Organizations formed by workers to protect their rights and improve working conditions. Labor unions played a role in advocating for fair wages and better working conditions for the growing middle class.
Social mobility: The ability for individuals or families to move up or down in social status based on factors such as education, occupation, or wealth. The development of middle class society offered some individuals upward social mobility opportunities while others experienced downward social mobility due to economic conflicts.