Technically, the word “tortoise” refers to any species that belongs to the family Testudinidae. Testudinidae is just one of many families belonging to the order Testudines, however, which includes turtles. For this reason, it can be said that all tortoises are turtles, but all turtles are not tortoises. Since neither tortoises nor turtles are found in Europe, the terms tend to be used interchangeably in many parts of the world.