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What is Amazon Route 53 and what is its primary purpose? What are the common DNS record types supported by Route 53, such as A, CNAME, and MX records? How do Route 53 routing policies, such as weighted and latency based routing, affect how traffic is directed? What are Route 53 health checks, and how do they support failover routing? How does Route 53 Resolver enable DNS resolution between a VPC and on premises networks? What is DNSSEC, and how does Route 53 support it to protect against DNS spoofing?
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What is a Route 53 alias record, and how is it different from a standard CNAME record?

Intermediate

Answer

An alias record is a Route 53 specific extension that lets you point a domain, including the root domain itself, directly to certain AWS resources such as a CloudFront distribution, an Application Load Balancer, or an S3 bucket configured for website hosting, and unlike a standard CNAME record, alias records can be used at the root of a domain and Route 53 does not charge for DNS queries that resolve through an alias record to an AWS resource.
aws route53 change-resource-record-sets --hosted-zone-id ABC123 --change-batch '{"Changes":[{"Action":"CREATE","ResourceRecordSet":{"Name":"example.com","Type":"A","AliasTarget":{"HostedZoneId":"Z2FDTNDATAQYW2","DNSName":"d123.cloudfront.net","EvaluateTargetHealth":false}}}]}'
Real-world example A company points its root domain, example.com without any subdomain, directly to a CloudFront distribution using an alias record, something that would not be possible using a standard CNAME record at the root level.

Common follow-ups: Why can alias records be used at the root domain while CNAME records cannot?;Does Route 53 charge extra for alias record queries?

Amazon CloudFront & Content Delivery;Elastic Load Balancing (ALB NLB & CLB)
All 7 Amazon Route 53 & DNS Management questions