What does "Loosely Coupled Architectures" mean?

Check out: well-architected services

Task Statement 2.1: Design scalable and loosely

Each component will be least affected by the existence of the other.

• Insert something into the queue
• Experience Component failure?
• Another node can pick it up
  So, the architecture isn't so rigid that a component failure will break
  the service completely.

Immutable Infrastructure

You don't want to store the state of the application on any ONE node.

• If that node fails, you lose the state