Terracotta, Terra cotta or Terra-cotta means baked earth in Italian. It originates from the latin words terra cocta which means the same. Terracotta is a type of ceramic tiles that was the very first way in which ceramic tiles were made. It is a clay-based unglazed ceramic that was originaly baked at a temperature of 500 to 550°C. Terracotta as a type of ceramic tiles is not used so often anymore, because it is relatively thick but still not very strong/hard. Big problem is also porosity and therefore terracotta is nowdays used mostly for hand made artistic ceramics. It is also used alot in vessels, pipes and surface embellishment in building construction.
Picture from: http://www.originalstyle.com/tile_stone_terracotta.htm