Drupal is an open-source Content Management System (CMS) used to build and manage websites and web applications. It is written in PHP and is known for its flexibility, scalability, and strong security features. Drupal allows organizations to create structured content (like pages, documents, news, and forms), manage users and permissions, and configure workflows without heavy custom coding. It is commonly used by government agencies, universities, and enterprises because it supports complex content structures and robust access control. It also has a large ecosystem of modules and themes that extend functionality and customize the look and behavior of a website.