CNAME stands for Canonical Name Record and is a DNS record used to route alias domains to a primary domain called the “canonical” domain. Another way to think about this is that it forwards domains and subdomains to other domains.
An example would be 19O3Studios.com (with the letter ‘O’). This domain is set to forward to 1903Studios.com. We did this because we pronounce 1903 as 19-Oh-3 Studios. The CNAME record is the record that is actually forwarding the traffic from the first domain to the second. This type of record can also be used for subdomains.
This type of record can also be used for subdomains. Because of that, it’s often used to verify ownership. This is done by requesting a CNAME record be setup with a specific subdomain forwarding to whoever is requesting the verification. Then they wait for a ping on their servers from that subdomain which tells them that you had the ability to edit the account which means you must own that domain or at the least have permission to edit it.