Epochs are particular periods of history that are marked by significant changes or events. They are often used to divide up long stretches of time into more manageable chunks, and can be used to refer to a specific era or period. EPOCHS are usually defined by the start and end of a major event, such as the beginning and end of a war or the rise and fall of an empire. They can also be used to refer to a period of time in which a certain culture or society flourished.