App. Fake news. Hashtag. What will be the word of the decade? And who decides?

One word was used to epitomize the entire 20th century.

Was it progress, to mark the march of civilization from buggies to astronauts and the iPhone?

Maybe upheaval, to delineate genocides and civic unrest?

No. Try jazz, to describe not only music, but the sweep and swing of the quintessential American century, and the cultural flows that invigorated it.

Who gets to decide such weighty, wordy things? The little-known American Dialect Society (ADS), founded in 1889, and dedicated to the study of the English language in North America.

ADS has been picking a word of the year since 1990, longer than any other entity. Its members selected jazz from dozens of possible words in January 2000.

Now fast forward to the first week of 2020, when 300 to 400 of the society’s language scholars are expected to meet in New Orleans to determine the word of 2019, as well as the even more consequential word of the decade that ends on New Year’s Eve. The word of the previous decade, by the way, was google, meaning “to search the internet.”

A fun bunch that’s not as tweedy or as uptight as you might think, society folks are known for their passionate, sometimes raucous, conclaves in which culture, politics, art, and technology are distilled to their dense essence — a single word or phrase freighted with enough punch and validity to capture the zeitgeist.

“We keep our finger on the pulse of words in America,” said ADS member Dennis Preston, a linguist from Oklahoma State University. "We don’t take ourselves too seriously, and we do it with a certain amount of whimsy.

“But never forget: Human language carries enormous meaning and symbolism."

Along with the ADS, dictionary publishers also pick words of the year. On Monday, Dictionary.com determined that the word of 2019 was existential, relating to world events involving climate change, gun violence, and changing democratic institutions.

Last month, Oxford Dictionaries selected climate emergency. Merriam-Webster has yet to announce its word.

“They’re just imitators,” sniffed Preston, who, at 80, believes he can get away with spewing tartly outrageous trash talk. "I’m happy Dictionary.com exercised their First Amendment rights coming up with existential.

“But the authentic word of the year will be chosen by the American Dialect Society. Nothing is so flattering as imitation.”

Many people in the word-of-the-year business rely on reams of data to determine what popular words were looked up on search engines or were trending on Twitter in any given year, noted Ben Zimmer, the internationally known linguist and language columnist for the Wall Street Journal, who once penned the “On Language” column for the New York Times Magazine.

But, said Zimmer, who is chair of the New Words Committee of the ADS, the society’s words are harvested during nominating sessions followed by lively debates and show-of-hands votes.

“It’s basically from hundreds of language scholars who have a pretty keen eye on the way language develops," Zimmer said. “We’ve never had fights. But discussions definitely become animated."

The words of the year chosen by the ADS are not necessarily new words; they could be old ones used in new ways, said Marianna Di Paolo, emeritus linguistics professor and ADS member from the University of Utah. One example is occupy, connected to the 2011 Occupy Wall Street protest against economic inequality.

“We observe what words have been salient,” she said.

During the last decade, the words of each year have bubbled out of the high-boiling soup of turbulent and tech-conscious times:

App in 2010. Occupy in 2011. Hashtag in 2012. Because X (a modern construction illustrated by the example, “Why would men wear capes? Because fashion”) in 2013.

#BlackLivesMatter in 2014. They as a singular pronoun in 2015. Dumpster fire (describing election-related “public discourse and preoccupations”) in 2016. Fake news in 2017. Last year, tender-age shelter (a euphemism referencing the facilities in which some immigrant children were separated from their parents). It beat out the wall (at the southern border).

The word of the decade won’t necessarily be one of the yearly winners, Zimmer said. The ADS draws up lists of candidates that may not become words of the year, but might still have a shot at being the 2010-19 representative.

There are “most likely to succeed” words, thought to have legs beyond any single year, such as ghost, a verb from 2015 meaning to abruptly end a relationship by cutting off communication, especially online.

Other possibilities include mansplaining (let a woman define it for you); selfie; Obamacare; and the Generation Z exclamation yeet, among many more examples.

Just for fun, the ADS likes to make lists of “most unnecessary” words, which definitely won’t represent the decade. These include manbun (a man’s hair pulled into a bun); baeless (without a bae, or romantic partner); and sharknado (a tornado full of sharks, as featured in the Syfy Channel movie of that name).

Frivolity aside, sometimes the linguists find themselves in serious discussions, such as debates about definitions of potential cultural appropriation, Zimmer said.

For example, the word woke, referencing being socially aware, was in contention for word of the year in 2016 because of what appeared to be a new adjective from an old verb, Zimmer said. However, African American linguists at the ADS meeting that year argued that it couldn’t be represented as new usage because the definition of woke as being conscious of racial discrimination in society and other forms of oppression and injustice had been used by African Americans in the 1960s, Zimmer said.

“There was a lot of discussion about that,” he added. “Dumpster fire became the word.”

Asked what he thinks the word of the decade will be, Zimmer was initially noncommittal.

But then he added, “I wouldn’t be surprised if they as a singular pronoun does very well,” he said. “It was word of the year in 2015 and has only grown since then, transcending he and she to represent nonbinary gender identity.”

But that’s just a guess, Zimmer stressed.

He added, “It’s what happens in the room in New Orleans that will make the difference.”