An "age" or "era" refers to a distinct period in history characterized by specific events, developments, or cultural trends. These timeframes can be defined by significant changes in society, technology, or the environment. For example, the Industrial Revolution marked a shift from agrarian economies to industrialized ones, fundamentally altering daily life. Different ages are often categorized by their dominant features, such as the Stone Age, which is known for early human tool-making, or the Digital Age, marked by the rise of computers and the internet. Each era contributes to the overall narrative of human progress and development.