"We now have a name for the disease and it's Covid-19," WHO chief Tedros Adhanom Ghebreyesus told reporters in Geneva.
It comes after the death toll from the virus passed 1000. Tens of thousands of people have been infected.
The word coronavirus refers to the group of viruses it belongs to, rather than the latest strain.
Researchers have been calling for an official name to avoid confusion and stigmatisation.
"We had to find a name that did not refer to a geographical location, an animal, an individual or group of people, and which is also pronounceable and related to the disease," the WHO chief said.
"Having a name matters to prevent the use of other names that can be inaccurate or stigmatising. It also gives us a standard format to use for any future coronavirus outbreaks."
There are now more than 42,200 confirmed cases across China. The number of deaths has overtaken that of the Sars epidemic in 2003.
On Monday, some 103 died in Hubei province alone, a daily record, and the national death toll is now 1016.
But the number of new infections nationally was down almost 20 percent from the day before, from 3062 to 2478.
China has "removed" several senior officials over their handling of the outbreak.
The party secretary for the Hubei Health Commission, and the head of the commission, were among those who lost their jobs.
They are the most senior officials to be demoted so far.