A production environment is the public-facing view of your website. It is where you install StagingPro, and any changes which StagingPro makes to the production environment means that will affect your live website will be affected.
A staging environment (stage) is a nearly exact near replica of a production environment for software testing. Staging environments are made to test codes, builds, Code builds and updates require Staging environments to ensure quality under a production-like environment before application deployment to the production environment.