Do you mean a... computer? Server is a software term. It is a process that listens for network requests.
At least since CGI went out of fashion, embedding a server right in your application has been the style. Serverless sees a return to the application being less a server, pushing the networking bits somewhere else. Modern solutions may not use CGI specifically, but the idea is the same.
If you did mistakenly type "server" when you really meant "computer", PaaS offerings already removed the need for businesses to manage computers long before serverless came around. "Serverless" appeared specifically in reference to the CGI-style execution model, it being the literal description of what it is.