Getting there could take practice, and in some cases, avoidance has been the preferred strategy. Peter Navarro, one of Mr. Trump’s top trade advisers and one of Nafta’s fiercest critics, seemed to dance around the issue while taking questions on NPR on Tuesday morning, safely referring to the new agreement as “the deal.”

Even Robert Lighthizer, the lead trade negotiator who spent more than a year brokering the new trade deal, referred to it as Nafta during a briefing with reporters on Monday afternoon.

For Mr. Trump, renaming Nafta was nearly as important as rewriting it. He spent years lashing out at the agreement and promising to scrap it, so giving it a new title was a critical part of ensuring his promise was kept.

It remains unclear whether the new name will take. On social media, critics of Mr. Trump have sneered at the name and some have suggested sticking to Nafta or amending it with a “2.0” to spite the president.

Dean Crutchfield, a branding and marketing strategist in New York, said that since the name was officially being changed in the text, it would probably take hold, as long as the news media used it.

“I think the more people see it, the more they will get accustomed to it,” Mr. Crutchfield said.

But that does not mean it will be embraced. According to Grover Hudson, an emeritus linguistics professor at Michigan State University, initialisms — which do not read as words — are easier to digest for shorter abbreviations. But long strings of words, such as the United States-Mexico-Canada Agreement, set off a desire for a convenient shorthand. Imagine if “scuba” — short for “self-contained underwater breathing apparatus” — were scrambled, he mused.

“It’s typical of Trump’s decisions in that you get something that’s not terribly better than what it replaced and worse in many ways,” Mr. Hudson said. “He wanted to have something new that he could claim was his, but all he could come up with was U.S.M.C.A.”