1. Plural of captcha; automated tests designed to verify that a user is human by requiring them to complete a task (such as identifying distorted text or images) that is easy for humans but difficult for computer programs.
Usage: Acronym for 'Completely Automated Public Turing test to tell Computers and Humans Apart'; Commonly used in computing and web security contexts; Often encountered when registering for accounts or submitting online forms

Examples

• Many websites use captchas to prevent spam and unauthorized access.
• I had to solve three captchas before I could create my new email account.
• The captchas on that site are so difficult that even humans struggle to complete them.
• Some captchas ask you to identify all the traffic lights in a grid of images.
• Accessibility advocates have criticized certain captchas for being hard to use with screen readers.