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CAPTCHA

American  
[kap-chuh] / ˈkæp tʃə /
Or captcha

noun

Digital Technology.
  1. an online test designed so that humans but not computers are able to pass it, used as a security measure and usually involving a visual-perception task.

    Site visitors must solve the “distorted text” CAPTCHA before posting comments.

  2. a computer program that generates such tests.


Etymology

Origin of CAPTCHA

First recorded in 2000–05; C(ompletely) A(utomated) P(ublic) T(uring) (Test to Tell) C(omputers and) H(umans) A(part); inspired by capture ( def. )

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

OpenAI’s safety tests for ChatGPT-4 revealed that AI has already developed the ability to scam human users into helping them pass Captcha tests.

From MarketWatch • Oct. 14, 2025

The A.I. even lied to the worker about why it needed the Captcha done, concocting a story about a vision impairment.

From New York Times • Mar. 15, 2023

Captcha: The ability to recognize crosswalks, buses, etc., is rare and highly prized in this civilization; humans with that skill are entitled to special benefits.

From Washington Post • Aug. 19, 2021

Other new security features including the option of authenticator apps - an extra security log-in step, and using Captcha images will also be added.

From BBC • Jul. 13, 2021

But she adds: “There is something backhanded about using authors’ personal statements as a Captcha tool for verifying the emotional resonance of their work.”

From Slate • Jul. 8, 2021

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