Tan

Tan may refer to:

• Tanbark, or tan, bark of certain species of tree
• Tan (color), pale, tawny shade of brown
• Tangent function, or tan, one of the main trigonometric functions
• Tanning, the process of making leather from hides
• Sun tanning, the darkening of skin in response to ultraviolet light
• Sunless tanning, the darkening of skin without ultraviolet light
• Tan (goat pattern), goat color pattern
• Tanfana, or Tan, ancient European goddess
• Tan (surname) (譚), a Chinese surname
• Chen (surname) (陳), a Chinese surname, pronounced "Tan" in Min Nan languages
• Lao Zi, posthumous name "Tan" or "Dān" (聃), philosopher of ancient China
• TAN Books & Publishers, a Catholic publishing company
• OS-tan, an Internet phenomenon on Futaba Channel
• Tan (album), a live album by the Polish rock band Kult
• Tahn, a yoghurt-based drink from the Middle East
• Tan (state), ancient Chinese kingdom situated in eastern Shandong Province
• Leborgne, nickname Tan, a patient of Paul Broca, on whose autopsy he identified Broca's area

"TAN" or "tan" may also be a three-letter abbreviation for:

• Tanzania (IOC and FIFA trigram; the ISO 3166 trigram is TZA)
• Total Acid Number, the measure of a lubricant's or crude oil's acidity
• Transaction authentication number in electronic banking
• Tree augmented naive Bayes, a probabilistic classifier based on applying Bayes' theorem
• Taunton Municipal Airport, IATA airport code TAN, airport in Taunton, Massachusetts
• Tax Deduction Account Number, issued by Indian Income Tax Department for deduction of tax at source.
• Thunderbirds Are Now!, a Detroit-based neo-post-punk band
• Tenth Avenue North, a Contemporary Christian band
• The Anime Network, an all-anime channel
• This Aint News, a social news website with a firm stance on preserving Freedom of speech
• Tiny area network, a local area network with 2–3 nodes connection, usually implemented for shared files, folders and printers in a home or small office environment
• Total amoniacal Nitrogen, Nitrogen content in form of ammonium