PHP (recursive acronym for PHP: Hypertext Preprocessor) is a widely-used open source general-purpose scripting language. It is especially suited for web development and can be embedded into HTML to create dynamic content.
HTML5 is the latest version of the language HTML. With new elements, attributes, and behaviors, and a larger set of technologies that allows the building of more diverse and powerful Web sites and applications.
CSS3 is the latest evolution of the Cascading Style Sheets language and aims at extending CSS2.1. It brings a lot of long-awaited features like transitions or animations, as well as new layouts like multi-columns, flexible box or grid layouts.