The related question is asked here, and I cannot figure out it.
It is called a DNS wildcard
As an aside (it's off-topic here): The standards are defined in RFC 4592. See also https://serverfault.com/questions/215042/dns-wildcard-vs-cname-subdomains
Do you mean redirecting all subdomains to the main domain? A domain bin ?
You might be looking for the term "URL canonization".