1. A security test presented on a website or app that requires a user to prove they are human by completing a task, such as identifying images, solving a puzzle, or typing distorted text.
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 creating accounts, logging in, or submitting forms online

Examples

• I had to solve a captcha before I could create my new email account.
• The website displayed a captcha asking me to identify all the traffic lights in a grid of images.
• After three failed login attempts, the system required me to complete a captcha.
• Many online forms use captcha to prevent spam and automated attacks.
• She struggled with the distorted text captcha and had to request a new one.
• The captcha verification took only a few seconds to complete.