Containerization is the encapsulation of an application and its dependencies into a container that can run on any computing environment. Containers are lightweight, standalone, and executable software packages that include everything needed to run an application, such as code, runtime, libraries, and configuration files. This approach ensures that applications run consistently across different environments, from development to production, by isolating them from the underlying infrastructure. Containerization enhances scalability, portability, and efficiency in software development and deployment. Tools like Docker and Kubernetes are commonly used to manage containers, allowing developers to create consistent and reproducible environments, which significantly reduces deployment time and mitigates the "works on my machine" problem.