Definition - What does HTML Validator mean?
Techopedia explains HTML Validator
An HTML validator basically checks whether the HTML and CSS codes in a Web page comply with the standards set by the World Wide Web Consortium (W3C). An example of an HTML validator is the W3C’s own Validator Suite found at http://validator.w3.org/. There is also a CSS validator, called Jigsaw, found at http://jigsaw.w3.org/css-validator/.