Docker is an open platform that helps with the universal distribution of applications. It has become a standard for certain types of container virtualization systems and has been adopted by various companies as a software container strategy.
Techopedia explains Docker
IT experts describe Docker as a tool that helps to ship code to servers in efficient ways. Docker deals with complex software stacks and distributed hardware infrastructure, helping IT people to avoid difficulties in bridging development, Q&A and production, as well as to avoid what Docker founder Solomon Hykes calls the "matrix from hell" - a situation where developers have to look closely at every type of distribution over every type of hardware and software scenario. The philosophy behind Docker is to help provide universal execution, using inherent Linux kernel properties that offer support for easier application handling. For example, instead of utilizing methods that would allow for library interdependency or other difficulties, Docker provides a smooth separation or "sandboxing," where a given library is installed multiple times in different containers so that each individual library instance is not interdependent with any other.
Docker experts describe this resource as a modern-day standard for code and application management, where adopting a given framework helps to make operations consistent and to increase the potential for universal deployment.