A technical description of a Linux container is a sandboxed process or processes isolated on a VM or bare-metal server.
These processes are isolated using the tried and tested mechanisms of Linux Namespacing, CGroups, and SELinux contexts. A good way of imagining a container is a way of packaging up applications or services. The container will only contain the files and libraries required for that application or service and will share the underlying components such as the kernel. The package of files and libraries is known as a container image.
Check out these great links which can help you dive a little deeper into running the Container practice with your team, customers or stakeholders.