Drupal is an open-source content management system (CMS) that allows individuals and organizations to create and manage dynamic websites, online stores, blogs, and other digital content. It is a modular framework that provides a wide range of features, including but not limited to user management, content creation and publishing, SEO optimization, theme customization, and integration with other applications. Drupal is written in PHP and is known for its flexibility, scalability, and security. It is often used for creating complex websites and applications for businesses, governments, nonprofits, and educational institutions.