Environment
also: environments
A separate place where a copy of your app runs, with its own settings and data. For example, one copy for testing and one for real users.
An isolated setup in which an application runs, defined by its machines, settings, data and connected services. Teams commonly keep development, staging and production environments so changes can be tested before they reach real users.
A theater has a rehearsal room and the main stage. Same play, same actors, but a mistake in rehearsal doesn't ruin the show for the audience.
Agents often ask which environment to change. A mistake in a test environment is harmless. The same mistake in the one real users rely on can break things for everyone.
This works in your local environment, but the live environment has a different database address. We'll need to add it there too.
Make this change in the test environment only. Don't touch the environment real customers use until I've tried it.
Thinking your app exists as one single thing in one place. The same code often runs in several environments at once, each with different settings and data.