The two terrier breeds are very similar, with the only major difference being the coats. The Smooth Fox Terrier has a smooth, flat, but hard and dense coat, whereas the Wire Fox Terrier coat should appear broken with a dense, wiry texture.
In show circles, the terms fox terrier and foxy are only used for these two breeds, but in other communities around the world, particularly rural and farming ares, these words are used for these breeds and also to refer to mixed-breed dogs or working terriers of fox terrier type, or to descendent breeds such as the Toy Fox Terrier and Miniature Fox Terrier, which are similar to each other.