Donald Trump’s apocryphal invention, which dates back to the noughties, takes title in dictionary’s annual reckoning of the most-used new expressions

“Fake news” has acquired a certain legitimacy after being named word of the year by Collins, following what the dictionary called its “ubiquitous presence” over the last 12 months.

Collins Dictionary’s lexicographers, who monitor the 4.5bn-word Collins corpus, said that usage of the term had increased by 365% since 2016. The phrase, often capitalised, is frequently a feature of Donald Trump’s rhetoric; in the last few days alone he has tweeted of how “the Fake News is working overtime” in relation to the investigation into Russian interference in the 2016 US presidential elections, and of how “Fake News [is] weak!”

Trump has used the term frequently, and claimed last week to have invented it – “the media is really, the word, one of the greatest of all [the] terms I’ve come up with, is ‘fake’ … I guess other people have used it perhaps over the years, but I’ve never noticed it,” he told an interviewer. This etymology was disputed by the dictionary.

Collins said that “fake news” started being used in the noughties on US television to describe “false, often sensational, information disseminated under the guise of news reporting”. Its usage has climbed since 2015, according to the dictionary, and really took off this year, with its ubiquity to be acknowledged with a place in the next print edition of the Collins Dictionary.

A number of other words related to politics and current affairs were also in its list of the words of the year. “Echo chamber”, defined as “an environment, especially on a social media site, in which any statement of opinion is likely to be greeted with approval because it will only be read or heard by people who hold similar views”,