The term 'Distinctive Span of History' can be summarized as an ERA, which is a three-letter word. An ERA is a period of time in history that is marked by certain characteristics or events. It is usually used to refer to a long period of time, such as the Middle Ages or the Industrial Revolution. It is also used to refer to shorter periods of time, such as the Roaring Twenties or the Age of Enlightenment. An ERA can be distinguished from other eras by its unique characteristics, such as its political, social, and economic developments.