What is the difference between continuous deployment to continuous delivery?
Long story short:

Continuous delivery is the capability to deploy the software to any given environment at a given point of time.  The objective is to perform push-button deployments of any version of the software to any environment on demand.

Continuous Delivery is often conflicted with Continuous Deployment.  Any change the developer makes gets deployed all the way up to Production is Continuous Deployment

The referenced article will give some info:
DevOps in nutshell