CAPTCHA
Americannoun
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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.
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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
Researchers recently showed that one system was able to hire a human online to defeat a Captcha test.
From New York Times • Jun. 10, 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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
