Release management is: "The definition, support, and enforcement of processes for preparing software for deployment into production". (Forrester Research, Inc.)
Release management manages the flow of change into production. It is the handoff between development, quality assurance, and production operation teams.
The goal of release management is to deploy application changes into production with high quality and without disrupting the business. But this process is often performed manually and is inefficiently connected to the rest of the application lifecycle, leaving a critical gap between application development and operations as well as creating a backlog of changes that must be made.