Covid19 stands for CoronaVirus Disease of the year 2019. COVI for CoronaVirus and D for Disease and 19 is the year of the outbreak.
As per WHO organization, each virus has a disease two different names are given. For example, HIV is a virus that causes AIDS.
Well, here coronavirus is a virus and as per WHO.int
severe acute respiratory syndrome coronavirus 2
The Taxonomy department of WHO is responsible for naming more here
What is interesting is before releasing the names – they are not securing the domains. And, in future, they should be not releasing the name before securing its matching domains.
I find COVID19.com registered:
Domain:covid19.comRegistrar:DYNADOT, LLCRegistered On:2020-02-11Expires On:2021-02-11Updated On:2020-03-04
And, also SARSCOV2
Domain:sarscov2.comRegistrar:1API GmbHRegistered On:2020-02-11Expires On:2021-02-11Updated On:2020-02-11
Both are very fresh registrations in dot com. In fact, not only dot com but it is at present registered in several other extensions.
I am taking dot com because you can determine the registration date in other extensions based on dot com