A server you can set up
An EC2 instance is a virtual machine that works much like a separate computer. A team chooses its computing power, installs software, and controls who can access it. AWS maintains the physical hardware; the team manages the software and settings inside the instance.
The “Elastic” in Elastic Compute Cloud means a team can add instances when an app gets busy and remove them when demand falls. The app must be set up to use that extra capacity. This ability is called elasticity.
One part of AWS
An app on AWS might run on EC2 and keep its files in S3. Saying “it’s on EC2” tells you where some software runs, but not where all its data is stored.