The term 'prefix with -lithic' refers to two words in the crossword puzzle: NEO (3 letters) and PALEO (5 letters). NEO is a prefix meaning 'NEW, ' while PALEO is a prefix meaning 'OLD.' Together, they form the terms 'Neolithic' and 'Paleolithic, ' which refer to two distinct periods of prehistory. The Neolithic period began around 10, 000 BCE and was characterized by the development of agriculture, the domestication of animals, and the use of stone tools. The Paleolithic period began around 2.6 million years ago and was characterized by the use of stone tools and the hunting and gathering of food.