A CAPTCHA or Captcha is a type of challenge-response test used in computing to ensure that the response is not generated by a computer. The process usually involves one computer (a server) asking a user to complete a simple test which the computer is able to generate and grade. ... en.wikipedia.org/wiki/CAPTCHA
A distorted image of letters and numbers used to prevent automated use of websites; Anything that a human must do to prove that they are not a computer en.wiktionary.org/wiki/CAPTCHA
An image containing a numerical or alphabetic code that can normally only be read and interpreted by a human. It is used to verify a form or other log in on a website to prevent computers from spamming the form. ... www.leapinghare.co.uk/help/glossary.html
Is used to decide whether a program or online service is being operated by a human or machine user. The most common form of Captchas are randomly generated images containing codes that are to be manually entered. A machine cannot decode the intentionally distorted letters and numbers. ... www.emsisoft.com/en/kb/articles/tec080424/
A SPAM prevention system now standard amongst websites. It requires the user to read and type a word from a distorted image. This is what you encounter when you sign up with Yahoo! Mail for the first time. Click here to see what it looks like. www.azurewebdesign.com/resources/glossary-of-web-terminology/
A captcha is program used to verify that a human, rather than a computer, is entering data. Captchas are commonly seen at the end of online forms and ask the user to enter text from a distorted image. ... glowvirtual.com/faqs/definitions.html
A device to hinder web-robots submitting data and eg creating spurious user accounts. CAPTCHA is a (contrived) acronym for 'Completely Automated Public Turing test to tell Computers and Humans Apart'. www.nashas-knitwear.co.uk/help/glossary.php