An exception to this is the Airedale Terrier, which is large in size and used for chasing down otters in and around water.

The term first appears in 1576, written as Terrar or Terrarius, in Johannes Caius" work De Canibus Britannicus (Of English Dogs). The term is used to describe fox and badger hunting dogs that pursue their quarries into the earth. The dogs belonging to this group are described as hunting dogs with an excellent nose.

Not included here in the Terrier group are the bull type terriers (such as the Staffordshire Bull Terrier, Amstaff, Boston Terrier, etc.) which descend from the ancient bull-and-terrier breeds and which were not usually utilized as vermin-controlling earth dogs.

The bull type terriers differ enough in physical appearance and temperament to be considered a separate group. The same goes for the Tibetan Terrier. However, terriers that were created purely as companion dogs, such as the Japanese Terrier, have nevertheless been included here, because their character and conformation remains close enough to the original working terriers.