Meowth's appearance is based on the Mankei Neko otherwise known as the "Begging cat" or the "Lucky Cat" in Japanese culture. Meowth's face has six little whiskers that look like antennas and a golden coin in the center. The coin, or charm, is known as a "Koban" and is associated with the Maneki Neko. The Koban itself is a coin that was equal to about one "ryo" (about a thousand US dollars) back in the feudal period of Japan's history. The Koban that the Maneki Neko holds is supposed to be worth ten million ryo and comes from the Japanese saying "neko ni koban". It means, "Gold coins for Cats" which is the equivilant to the Western saying "Pearls before swine". Interestingly enough, Meowth's move "Pay Day" in Japanese is known as "Neko ni Koban", literally the Japanese idiom.
The Japanese Bobtail is the predominant breed of cats in Japan. Meowth itself does not have a bobbed tail, but its tail does retain the same swirl that a bobtail cat might have. Calico coloring is also favored and therefore, Meowth, much like Menaki Neko, has tipped ears, paws, and tail. The Meowth species are always depicted with large mouths, probably since it is a play on its name origins.
Meowth's name in Japanese is written which is translated into "Ni-ya-su"- where the "su" stands in for the "th" sound. Also sometimes referred to as "Nyarth". The name originates from the Japanese sound of a meowing cat ("Nyaa~") and the last sound in the English word for mouth. Respectively, the English translation becomes "Meowth". The idea of Meowth and Mouth is played on extensively in the anime where Team Rocket's Meowth makes puns referring to his mouth. (That and he talks an awful lot). I sometimes wonder if the name also comes from a noisy cat. A few names from other languages: