The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser.
Cascading Style Sheets is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML.
Ruby is an interpreted, high-level, general-purpose programming language which supports multiple programming paradigms.
PHP is a general-purpose scripting language geared toward web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1994.
Structured Query Language aka SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system, or for stream processing in a relational data stream management system.