CAPTCHA

6 synonyms for CAPTCHA, grouped by meaning and by how common each one is.

Noun — A small test on a website meant to tell a real person apart from an automated programme, such as reading distorted letters, picking out images that contain a certain object, or ticking a box that quietly measures how the visitor behaves.

Synonyms

Everyday swaps

Common words most readers know — safe in any writing.

gate challenge

Rare, literary or technical

Precise, but they will stand out — check the sense before using one.

human verification bot check challenge-response test human test

Synonyms by Meaning

1. noun computing

A small test on a website meant to tell a real person apart from an automated programme, such as reading distorted letters, picking out images that contain a certain object, or ticking a box that quietly measures how the visitor behaves.

“I failed the CAPTCHA twice before it accepted that I could see a bicycle.”

human verification bot check challenge-response test human test

2. verb informal, computing

To place such a test in front of a page, form or action.

“We captcha'd the contact form because it was being flooded with spam.”

gate challenge

How to use CAPTCHA

The word patterns that sound natural to a native speaker.

solve a CAPTCHA fail a CAPTCHA CAPTCHA challenge image CAPTCHA invisible CAPTCHA

Usually written in capitals as CAPTCHA, though lower-case captcha is common in casual writing. The verb use is informal.

Etymology

An acronym of completely automated public Turing test to tell computers and humans apart.

Full origin of CAPTCHA →

Frequently asked questions

What is the difference between a CAPTCHA and reCAPTCHA?

CAPTCHA is the general name for any test designed to separate people from automated programmes. reCAPTCHA is one particular branded service that provides such tests, so every reCAPTCHA is a CAPTCHA, but many CAPTCHAs come from other providers or are built in-house.

Why do CAPTCHAs ask about traffic lights and bicycles?

Picking objects out of photographs is a task people handle easily and automated scripts historically handled poorly, so it works as a rough divider. The same answers can also be used as labelled training data for image-recognition systems.

Why does a CAPTCHA sometimes pass with just a tick box?

Newer tests do not rely only on the puzzle. They look at signals such as mouse movement, timing and browser characteristics, and if those look consistent with a person, the visible challenge is reduced to a single tick.

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Nearby words

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