Definition from Wiktionary, the free dictionary
CAPTCHA (plural CAPTCHAs)
- A distorted image of letters and numbers used to prevent automated use of websites.
- I find CAPTCHAs very difficult to read.
- (by extension) Anything that a human must do to prove that they are not a computer.
- audio CAPTCHA, a distorted audio file containing a voice reading numbers.
- visual CAPTCHA, when a distinction must be made between an audio CAPTCHA and a distorted image.
a distorted image of letters and numbers used to prevent automated use of websites