A cousin domain, which is also referred to as a look-alike domain, is a Domain Name System (DNS) domain that looks similar to another name when rendered by a Mail User Agent (MUA).
For example, groupA.example is a cousin domain of group.example. Other examples include misspellings of a domain, such as domainsample.com and domainsapmle.com.
Cousin domains typically are created as a phishing tool to spoof your brand and domain name.