CD and continuous deployment are normally used interchangeably. However, there is a minor difference.
CD is the application deployment into an environment that is not production, so it can be development, QA, stage, pre-production, and so on.
Continuous deployment is the application deployment into the production environment.
We need to understand the way an application is deployed in production and non-production environments manually and then try to automate that process. The automated approach of application deployment doesn't change. It is all about the location where the application is getting deployed.
CD makes the application package production ready. Continuous deployment goes through end-to-end automation for release management and manual intervention is not required.
A minor difference is the manual approval process in the environment that makes CD and continuous deployment different from each other. In the case of a production environment...