No, CodeIgniter is not a programming language. It is a web application framework built using the PHP programming language. A framework provides a structured, reusable set of libraries or classes for a specific purpose. In the case of CodeIgniter, it offers classes for tasks common in web development, like handling database connections, sending emails, maintaining sessions, manipulating images, and more. Developers use PHP language to interact with these libraries and create their applications using CodeIgniter's structure.