Frequently Used Terms in AWS simplified

Amazon S3

S3 is short for Simple Storage Service. S3 is an object storage in the cloud that works just like files and directories on our local computer. It works on the basis of containers called buckets that can be used to store files and directories as objects.

AWS users can use S3 to store files privately or share them in public. It can also be used to serve static websites i.e. web pages that only need client-side display and processing.

Amazon EC2

EC2 is an abbreviation of Elastic Compute Cloud which consists of a physical AWS data center setup. An AWS data center setup consists of hundreds of physical servers with high speed and high availability internet connectivity and backup power facilities.

AWS Region

AWS Region is a physical location (town/city) for AWS data centers. There are more than 20 such locations worldwide. Each location has a region code such as ap-south-1 for Asia Pacific (Mumbai) region. more on AWS Regions

EC2 Instance

An EC2 instance is a cloud/virtual server formed by putting together vCPU (virtual CPU), RAM, Storage, Network Services and Bandwidth combinations which are all billed separately on usage.

EC2 instances are classified into different types based on combinations of vCPU, RAM, and vCPU usage scenarios such as burst-able processing power. For example, the t2.micro instance type is a burst-able performance instance with 1 vCPU and 1 GB RAM. t2.micro usage is AWS Free Tier eligible. more on EC2 Instance types

EC2 instances are usually setup with an operating system based on Linux or Windows, although Linux instances are the most popular for web applications that do not need a Windows environment.

AWS users can opt to setup their EC2 instances in any EC2 region. Some EC2 regions may need an additional opt-in.


You may have noticed that while defining an EC2 instance we made no mention of disk storage. That is because data storage is available as a separate AWS component called Elastic Block Storage (EBS). You can add storage as a EBS volume to an EC2 instance to serve as it's primary or additional disk storage requirements. more on EBS volumes

EBS has different types based on the underlying physical storage resources such as:

  • Storage volume based on magnetic drives: standard
  • General Purpose SSD volume that balances price performance for a wide variety of transactional workloads: gp2
  • High performance SSD volume designed for business-critical latency-sensitive applications: io2

Amazon Machine Image (AMI)

AMIs are pre-built, ready-to-use virtual machine templates that are used to spawn new Amazon EC2 instances (cloud servers) in AWS Regions. more on AMI

Elastic IP

Elastic IP is the AWS term used for a fixed/static IP address. Once you associate an Elastic IP with your EC2 instance its IP will not change even if you stop and start the instance. more on Elastic IP

Security Group

Security group is a setup of inbound and outbound traffic rules for your EC2 instance. It is a firewall with specifications for ports that need to be opened for your EC2 instance. more on Security Groups

EC2 Key Pair

EC2 key pairs are SSH keys used to sign-in to your EC2 instance using a SSH client. A key pair when generated, consists of a public key that is stored in AWS and associated with your EC2 instance and a private key that you can download and use to sign-in via SSH. more on EC2 Key Pairs

Some things to note when using an EC2 key pair:

  • An Amazon EC2 key pair is tied to a particular AWS region.
  • You can associate only one Amazon EC2 key pair on an instance. If you want to allow multiple users to log in, they must all have a copy of the private key.