The term 'Period Revolution' refers to a period of time in which there was a great amount of social, political, and economic change. The crossword solution for the term is 'YEAR, ' which indicates that this period of revolution occurred over a span of one year. This period of revolution was characterized by a number of significant events, such as the French Revolution, the American Revolution, and the Industrial Revolution. These events had a lasting impact on the world and shaped the modern world as we know it today.