HTML stands for Hyper Text Markup Language. A markup language is a set of markup tags. HTML documents contain HTML tags and plain textHTML documents are also called web pages. HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items.
CSS stands for Cascading Style Sheets. Cascading Style Sheets (CSS) is a simple mechanism for adding style (e.g., fonts, colors, spacing) to Web documents. Styles define how to display HTML elements.External Style Sheets can save a lot of work. External Style Sheets are stored in CSS files.