JavaScript Object Notation (JSON) (http://json.org/), a standard, machine- and human-readable information interchange format. Here's what the AZs in the us-east-1 (North Virginia) region look like represented as JSON:

aws ec2 describe-availability-zones --output json 
{ 
"AvailabilityZones": [ 
        { 
"State": "available", 
"RegionName": "us-east-1", 
"Messages": [], 
"ZoneName": "us-east-1a" 
        }, 
        { 
"State": "available", 
"RegionName": "us-east-1", 
"Messages": [], 
"ZoneName": "us-east-1c" 
        }, 
        { 
"State": "available", 
"RegionName": "us-east-1", 
"Messages": [], 
"ZoneName": "us-east-1d" 
        }, 
        { 
"State": "available", 
"RegionName": "us-east-1", 
"Messages": [], 
"ZoneName": "us-east-1e" 
        } 
    ] 
}