What do you understand by Docker?

Note: As we are going through Docker interview questions and answers it is very important to have a brief over what is Docker.

Docker presents a containerization platform packaging applications along with its dependencies together in a container form. It is yours that the applications work seamlessly under any environment (no matter if it is a test, development of production). The Docker containers wrap the piece of software in an entire file system containing the essentials like code, runtime, system libraries, system tools and many more. It also wraps everything which is installed on a server guaranteeing its run time regardless of the environment.