a computer program that is designed to recognize the difference between human users and machines, often showing letters or numbers with their shape changed slightly 人机验证,验证码(一种区分计算机和人类用户的计算机程序) The captcha can only be solved by humans. 只有人类能识别验证码。
Word OriginAn acronym from Completely Automated Public Turing test to tell Computers and Humans Apart.