captcha

noun

capt·​cha ˈkap-chə 

variants or CAPTCHA

: a test to prevent spamming software from accessing a website by requiring visitors to the site to solve a simple puzzle (typically by reading and transcribing a series of numbers or letters from a distorted image) in order to gain access

The point of the CAPTCHA is that reading those swirly letters is something that computers aren't very good at. If you can read them, you're probably not a piece of software run by a spammer.

—Lev Grossman

Examples of captcha in a Sentence

Recent Examples on the Web

Already, some services such as Roblox use very difficult CAPTCHAs, likely to keep ahead of similar improvements in computer vision. —Benj Edwards, Ars Technica, 18 July 2023

The redirections lead to sites pushing fake tech support, fraudulent lottery wins, and push notification scams, the latter of which trick visitors into subscribing to push notifications by displaying fake captcha dialogs. —Kevin Purdy, Ars Technica, 9 Oct. 2023

Most internet users will have done some form of data labeling: identifying images of traffic lights and buses for online captchas. —Niamh Rowe, WIRED, 16 Oct. 2023

Bing Chat has recently been seen on Twitter solving CAPTCHA tests designed to screen out bots, which may also delay the wider release of Bing's image-processing features. —Benj Edwards, Ars Technica, 18 July 2023

While some architectures can successfully navigate the human factor—such as the proof of work consensus, which was originally designed as a captcha mechanism in the early 2000s—there are multiple architectures that are more susceptible to external attacks. —Dmitry Mishunin, Forbes, 28 Nov. 2023

The idea is to attach a cryptographic tag to a piece of content that verifies it was created by a human, as determined by its process of creation—a sort of captcha for digital files. —Christopher Beam, WIRED, 14 Sep. 2023

By 2014, Google found that an AI could solve the most complicated CAPTCHAs with 99 percent accuracy. —Kate Lindsay, The Verge, 24 Feb. 2023

Elon Musk referenced another one at last month’s Viva Technology conference in Paris: CAPTCHA puzzles. —Emily Dreibelbis, PCMAG, 5 July 2023

Word History

Etymology

Completely Automatic Public Turing test to tell Computers and Humans Apart (with deliberate pun on capture entry 1)

First Known Use

2001, in the meaning defined above