Since lithos in Greek means "stone", the Neolithic period is the "new" or "late" period of the Stone Age, in contrast to the Paleolithic period ("old" or "early" period) and the Mesolithic period ("middle" period) of the Stone Age. The use of polished stone tools came to different parts of the world at different times, but the Neolithic Age is usually said to begin around 9000 B.C. and to end around 3000 B.C., when the Bronze Age begins. The Neolithic is the era when the farming of plants and animals begins, and when, as a result, humans first begin to create permanent settlements.