A subnet in AWS is a segmented section of a Virtual Private Cloud (VPC) where you can launch AWS resources. Subnets help in organizing resources, controlling network traffic, and securing your applications. Subnets are defined within a specific Availability Zone (AZ) of a region.
Example code snippet to create a subnet:
aws ec2 create-subnet --vpc-id <vpc-id> --cidr-block 10.0.1.0/24 --availability-zone us-west-2a