The process of continuously deploying production-ready features into the production environment, or to the end user, is termed as Continuous Deployment.
Continuous Deployment in a holistic sense means, the process of making production-ready features go live instantly without any intervention. This includes building features in an agile manner, integrating and testing them continuously, and deploying them into the production environment without any breaks.
Continuous Deployment in a literal sense means, the task of deploying any given package continuously in any given environment. Therefore, the task of deploying packages into a testing server and a production server conveys the literal meaning of Continuous Deployment.