Donald Trump's inauguration has been marred by a row over whether one of his key advisors told falsehoods or "alternative facts".
As the controversy spread, the social media team at the Merriam-Webster Dictionary clarified the definition of the word.
"A fact is a piece of information presented as having objective reality," the company said in a tweet.
The tweet linked to a trending page on the company's website, which says searches for "fact" spiked after Trump senior aide Kellyanne Conway claimed controversial comments made by the White House press secretary were not lies, but "alternative facts".
Mr Trump's press secretary, Sean Spicer, used his first White House press briefing to attack the press over what he called "deliberately false reporting" around the inauguration.
He insisted the President's swearing-in was watched by the "largest audience to ever witness an inauguration, period".
The claim contradicts all available evidence.
Speaking to Chuck Todd on NBC's Meet the Press, Ms Conway was asked to explain why Mr Spicer "uttered a falsehood" about having the "largest crowd in inauguration history".
"Don’t be so overly dramatic about it, Chuck," Ms Conway responded. "You’re saying it’s a falsehood... Sean Spicer, our press secretary, gave alternative facts to that."
Mr Todd said four of the five facts Mr Spicer gave were not true, adding: "Look, alternative facts are not facts. They're falsehoods."
Responding to Ms Conway's "alternative facts" comment, the Merriam-Webster team clarified: "In contemporary use, fact is generally understood to refer to something with actual existence, or presented as having objective reality."
