He had not previously encountered the term, according to a senior White House official who admitted to CNN that the president was taken by surprise.

Trump had said as much at the time, saying “I’ve never heard that” before calling it the “nastiest question.”

“He thought the reporter was calling him a chicken,” the official said, adding that Trump was “reasonably” frustrated with the phrase.

The acronym was created in early May by a Financial Times columnist and is now commonly used by some on Wall Street to suggest that traders shouldn’t worry excessively about Trump’s tariff threats, as he typically retreats.

Trump also vented his frustrations to his team following the exchange, sources familiar with the matter said.

He was not only irked by the term itself but also by his team’s failure to tell him about the phrase gaining traction.

It’s a window into what may offend Trump the most: He took clear umbrage with the idea that people perceive his tariff adjustments as weakness.

Trump’s real-time response also demonstrated his view that the shorthand diminished what he sees as an essential negotiating tactic on trade.

He elaborated on Wednesday that occasionally he proposes “a ridiculously high number” for tariff rates and then softens his stance if other countries meet his demands.

“It clearly bothered him, primarily because it demonstrated a lack of understanding about how he actually utilises those threats for leverage,” said one person familiar with the matter.

“But obviously he’s not a guy who looks kindly on weakness, so the idea anyone would think that with respect to his actions isn’t received well.”

Trump, in just the last week, has threatened 50 per cent tariffs on the European Union, then extended the deadline in return for more concrete talks and has threatened to re-escalate his China trade war in an effort to secure compliance with last month’s agreement.

Last month, he also imposed a 145 per cent tariff on imported Chinese goods, before bringing that back down to 30 per cent this month.

The TACO acronym’s journey to the Oval Office is, in and of itself, a telling narrative about the current information environment.

It originated with a May 2 column from Robert Armstrong, a Financial Times commentator and author of the publication’s popular finance newsletter “Unhedged.”

Armstrong coined the phrase as a way of capturing Trump’s frequent willingness to walk back, pause or provide carve outs from his most expansive tariff threats.

The idea, in short, is that Trump’s threats had created a pattern of driving stocks down, only to see them surge when he changed course weeks later.

He used the term to try and explain the steady upward trajectory taking place in late April, which he wrote had “a lot to do with markets realising that the US administration does not have a very high tolerance for market and economic pressure, and will be quick to back off when tariffs cause pain.

This is the TACO theory: Trump Always Chickens Out.”

The acronym became something of a running joke on finance Twitter, the informative and generally good-humoured corner of X where financial commentators and analysts debate the day’s most interesting, market moving or, at times, arcane topics.

Within a few weeks, the TACO trade had become a fixture of Wall Street chatter and started appearing in client notes from financial analysts and economists.

The rapid acceleration of the acronym’s role in finance lexicon caught Armstrong, who has been sharply critical of the economic merits of Trump’s tariffs, by surprise.

“The mysteries of social media and media in general are still completely hidden to me,” Armstrong said on the FT’s “Unhedged” podcast.

“The outcome I really, really hope does not happen is that this has anything to do with the president stopping his habitual chickening out,” Armstrong added.

“Let us state clearly, chickening out is good and something to be celebrated. Bad policy chickening out — hooray.”

Trump made it clear to the reporter on Wednesday that he preferred a different description.

“You call that chickening out?” Trump asked. “It’s called negotiation.”