A wallaby is any of about thirty species of macropod (Family Macropodidae). It is an informal designation generally used for any macropod that is smaller than a kangaroo

Kangaroo

A kangaroo is a marsupial from the family Macropodidae . In common use the term is used to describe the largest species from this family, especially those of the genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern Grey Kangaroo and Western Grey Kangaroo. Kangaroos are endemic to the country...

 or wallaroo

Wallaroo

A Wallaroo is any of three closely related species of moderately large macropod, intermediate in size between the kangaroos and the wallabies. The name "wallaroo" is a portmanteau of wallaby and kangaroo. The term is not generally used by Australians...

 that has not been given some other name.
Very small forest-dwelling wallabies are known as "pademelon

Pademelon

Pademelons are small marsupials of the genus Thylogale. They are usually found in forests. Pademelons are the smallest of the macropods...

s" (genus Thylogale) and "dorcopsises" (genera Dorcopsis

Dorcopsis

The dorcopsises are the marsupials of the genera Dorcopsis and Dorcopsulus. They are found in the tropical forests of New Guinea and Southeast Indonesia. They are placed in the subfamily Macropodinae, along with other Australasian marsupials such as wallabies, kangaroos, tree-kangaroos, pademelons,...

and Dorcopsulus

Dorcopsulus

Dorcopsulus is a genus of marsupial in the Macropodidae family. It contains the following species:* Macleay's Dorcopsis * Small Dorcopsis...

,) The name, "wallaby", comes from the Eora

Eora

The Eora are the Aboriginal people of the Sydney area, south to the Georges River, north to the Hawkesbury River, and west to Parramatta. The indigenous people used this word to describe where they came from to the British. "Eora" was then used by the British to refer to those Aboriginal people...

 Aboriginal tribe who were the original inhabitants of the Sydney

Sydney

Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

 area.