Maltese cat is a name that is often given to any cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

 whose fur is either completely, or primarily, gray or blue and is of indeterminate breed. Many cats with such colouration are supposedly present on the island of Malta

Malta Island

Malta Island is the largest of the three major islands that constitute the Maltese archipelago and Republic of Malta. Malta is in the middle of the Mediterranean Sea directly south of Italy and north of Libya. The area is 246 km² . The capital is Valletta, largest city is Qormi and the largest...

, which may have given rise to the use of the adjective in this context. There are several cat breeds that always produce blue or gray fur, of whom the adjective may be used. These are the Russian Blue

Russian Blue

The Russian Blue is a cat breed that has a silver-blue coat. These cats are known to be highly intelligent and playful but tend to be timid around strangers...

, the Chartreux

Chartreux

The Chartreux is a breed of domestic cat from France and is recognised by a number of registries around the world. It is not recognised by the GCCF in the UK, ostensibly for being too similar to the British Shorthair, one of whose colours is a similar blue-grey. The Chartreux is large and...

 and the Korat

Korat

Korats are a slate blue-grey shorthair domestic cat with a small to medium build and a low percentage of body fat. Their bodies are semi-cobby, and surprisingly heavy for their size. They are intelligent, playful, active cats and form strong bonds with people. Among Korats' distinguishing...

. There are several other breeds that often produce blues such as the British Shorthair

British Shorthair

The British Shorthair is a domesticated cat whose features make it a popular breed in cat shows. It has been the most popular breed of cat registered by the UK's Governing Council of the Cat Fancy since 2001, when it overtook the Persian breed....

. The blue variant of this breed was so common that many thought it was its own breed called the British Blue.

Other meanings

In literature

Literature

Literature is the art of written works, and is not bound to published sources...

, "The Maltese Cat" is the title of a short story

Short story

A short story is a work of fiction that is usually written in prose, often in narrative format. This format tends to be more pointed than longer works of fiction, such as novellas and novels. Short story definitions based on length differ somewhat, even among professional writers, in part because...

 by Rudyard Kipling

Rudyard Kipling

Joseph Rudyard Kipling was an English poet, short-story writer, and novelist chiefly remembered for his celebration of British imperialism, tales and poems of British soldiers in India, and his tales for children. Kipling received the 1907 Nobel Prize for Literature...

. The story is about a polo

Polo

Polo is a team sport played on horseback in which the objective is to score goals against an opposing team. Sometimes called, "The Sport of Kings", it was highly popularized by the British. Players score by driving a small white plastic or wooden ball into the opposing team's goal using a...

 match set in British colonial

British Raj

British Raj was the British rule in the Indian subcontinent between 1858 and 1947; The term can also refer to the period of dominion...

 India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, told from the point of view of one of the ponies, a gray named the Maltese Cat.