A terrapin is one of several small species of turtle living in fresh or brackish water. Terrapins do not form a taxonomic unit and may not be related. Many belong to the families Geoemydidae and Emydidae. The name "terrapin" is derived from torope, a word in the Native American Algonquian language that referred to the species Malaclemys terrapin. It appears that it became part of common usage during the colonial era of North America and was carried back to Great Britain. Since then, it has been used in common names for testudines in the English language.