CAPTCHA

or cap·tcha

[ kap-chuh ]

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.

Word History and Origins

Origin of CAPTCHA¹

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

Called "captcha," it's essentially a test that's easy for a human to complete, but difficult or impossible for a computer to do.

From The Daily Beast