CAPTCHA

  initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart"

  CAPTCHA tests often involve asking the user to type in text that is displayed in an obscured image or audio file.

  A Turing test is any system of tests designed to differentiate a human from a computer. It is named after famed computer scientist Alan Turing. The term was coined by researchers at Carnegie Mellon University.