Web development is a broad term for the work involved in developing a web site for the Internet (World Wide Web) or an intranet (a private network).

PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. wikipedia.org

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles. wikipedia.org

HyperText Markup Language (HTML) is the main markup language for web pages. HTML elements are the basic building-blocks of webpages. wikipedia.org

Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation (that is, the look and formatting) of a document written in a markup language. wikipedia.org

Structured Query Language (SQL) is a programming language designed for managing data in relational database management systems (RDBMS). wikipedia.org

A system administrator, or sysadmin, is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems; especially multi-user computers, such as servers. wikipedia.org

A database administrator (short form DBA) is a person responsible for the installation, configuration, upgrade, administration, monitoring and maintenance of physical databases.

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. wikipedia.org

Windows Server is a brand name for a group of server operating systems released by Microsoft. wikipedia.org

A network administrator, network analyst or network engineer is a person responsible for the maintenance of computer hardware and software that comprises a computer network. This normally includes deploying, configuring, maintaining and monitoring active network equipment. wikipedia.org