What is elastic ip in AWS?

An elastic IP address is a public static IPv4 address that is reachable from the Internet. Primarily, elastic IP addresses are managed by AWS to maintain its dynamic cloud computing services and within the AWS infrastructure, clients have virtual private clouds (VPC), and in the VPCs, users have instances. So while launching an EC2 instance, you obtain a public IP address by which that instance is reachable from the internet. Once you suspend that instance and restart the instance you get a different public IP for the same instance. So it's basically a difficult to connect your instance from the internet for not having a static IP. To surmount this problem, an elastic IP is attached to an instance which doesn't switch after you stop/start the instance. To recapitulate, elastic IP is a permanent IP for the instance.