(ta-too′ĭng )

[Tahitian tatau]

1. Indelible marking of the skin produced by introducing minute amounts of pigments. Tattooing is usually done to produce a certain design, picture, name, or words. When it is done by a nonprofessional, sterile procedures may not be used and hepatitis B or C or HIV may be transmitted to the consumer. The technique may also be used to conceal a corneal leukoma, to mask pigmented areas of skin, or to color skin to look like the areola in mammoplasty.
2. In radiation therapy, the induction of a small amount of indelible pigment under the skin to designate an area to be treated with radiation.