The Upper Paleolithic period is often referred to as the Late Stone Age, indicating the end of the Stone Age period. It is also sometimes called the Late Pleistocene era, as it coincided with the final stages of the Pleistocene Epoch. Other synonyms for Upper Paleolithic include the Upper Old Stone Age, Upper Palaeolithic, and Late Paleolithic. The period saw a significant change in human behavior and evolution, with the emergence of sophisticated tools, the development of art, and new forms of social organization. These synonyms are useful in academic discussions and can help to avoid repetition when describing this important era of human history.