WHO director-general Tedros Adhanom Ghebreyesus said the epidemic was "very much an emergency" for China but also "one that holds a very grave threat for the rest of the world".
He said the virus had been named COVID-19, explaining that it was important to avoid stigma and that other names could be inaccurate.
WHO had earlier given the virus the temporary name of "2019-nCoV acute respiratory disease" and China's National Health Commission this week said it was temporarily calling it "novel coronavirus pneumonia" or NCP. It was chosen in order to avoid references to a specific geographical location, animal species or group of people.
The U.N. health agency said there were still many critical but unanswered questions about the virus, including what animals it came from, how exactly it is spread between people and how best to treat infected patients.
World Health Organization also notes that using animal species in the name can create confusion, such as in 2009 when H1N1 was popularly referred to as "swine flu". This name gave some the impression it could be spread by pigs, resulting in significant damage to the pork industry.
"Viruses can have more powerful consequences than any terrorist action", he told reporters later.
To date, the virus has infected more than 43,000 people and has killed 1,007, with 99% of the cases found in China.
Scientists from around the globe are uniting forces to discuss ways to fight this virus.
"To defeat this outbreak, we need answers to all those questions and more", Tedros said.
JPMorgan analysts downgraded forecasts for Chinese growth this quarter and Norwegian energy consultancy Rystad Energy predicted the outbreak would cut growth in global oil demand by a quarter this year.
Tedros, who has repeatedly urged countries affected to share their data, called for global "solidarity".
"That is especially true in relation to sharing of samples and sequences".
To those under the lock-down in China, he said he and the participants "stand with you in solidarity, and we wish you courage, patience, success and good health in these extremely trying circumstances".
"We hope that one of the outcomes of this meeting will be an agreed roadmap for research around which researchers and donors will align", Tedros told the meeting.
Several companies and institutes in Australia, China, France, Germany and the United States are racing to develop a vaccine - a process that normally takes years. A total of 1,017 people have died in the outbreak.
World stocks, which had seen rounds of selloffs due to the novel coronarivus' impact on China's economy and ripple effects round the world, kept rising towards record highs on Mr. Zhong's comments.