Containers are portable and lightweight alternatives to virtual machines that allow developers to package, isolate, and deploy applications across different cloud environments. Containers simplify the building and deploying of cloud native applications by providing consistent and efficient development, testing, and production environments. Containers also offer benefits such as rapid provisioning, high scalability, resource optimization, and security isolation. Reference:
What are containerized applications? from Google Cloud
What are containers and why do you need them? from IBM Developer
Embracing containers for software-defined cloud infrastructure from Red Hat