A tattoo is a marking made by inserting ink into the skin to change the pigment for decorative or other reasons. It is said that the word tattoo has two major origins- from the Polynesian word "ta" which means striking something and from the Tahitian word "tatau" meaning to mark something. It began over 5000 years ago and tattoo is as diverse as the people who have them on their skin.
Tattoos on human are a type of decorative body modification while tattoos on animals are most commonly used for identification or branding. For Polynesian, Samoan, Tongan, etc. it is called tatau. In Tahitian, tatu. The word tatau was immediately adapted into English, the pronunciation was changed to conform to English phonology as tattoo. 
Sailors later introduced both the word and reintroduced the concept of tattooing to Europe. Tattoo fanatics may refer to tattoos as ink, tats, art, pieces or work. The tattooists can also be called as Artists.
Tattooing has been practiced worldwide. It has been a Eurasian practice at least since Neolithic period. Otzi the Iceman was found in the Otz valley in the Alps, dating from the 4th to 5th millennium BC, had more or less 57 carbon tattoos consisting of small dots and lines on his lower spine, on his right ankle and behind his left knee. Other mummies like the Mummy of Amunet from ancient Egypt was found dating from the end of the 2nd millennium BC bearing tattoos.
Pre-Christian Celtic, Germanic and other central and northern European tribes were often heavily tattooed, according to surviving accounts.
Tattooing in Japan is thought to go back to the Paleolithic era, some ten thousand years ago. Plenty other cultures have had their own tattoo traditions, ranging from rubbing cuts and wounds with ashes, to hand-pricking the skin to insert inks or dyes.
In the Western world today, tattooing has originated from Polynesia by 18th century explorers. It became popular among European sailors, before it became popular worldwide.
Despite the growing fascination with tattooing of the social sciences as well as the people worldwide and the immense popularity of body tattoos themselves, the practice has not left much of a historical record.
Source : http://ezinearticles.com/?Tattoo---The-Beginning-of-the-Body-Art&id=2574797
