captcha
noun /ˈkæptʃə/
/ˈkæptʃə/
(also CAPTCHA)
[countable, uncountable]- 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。
词源An acronym from Completely Automated Public Turing test to tell Computers and Humans Apart. - The captcha can only be solved by humans.