As we hit the second anniversary of the first confirmed U.S. case of COVID-19, the pandemic continues to impact our day-to-day life in ways big and small, right down to the very language we use.

Among hundreds of new terms added to Merriam-Webster's online dictionary in 2021, a significant number of them were coined during the ongoing pandemic.

"We saw the word long hauler added to the dictionary," said Merriam-Webster editor-at-large Peter Sokolowski. "There’s super-spreader and long COVID, vaccine passport and vaccine hesitancy."

Sokolowski said that COVID-19 also made its mark among thousands of old words that received new definitions in 2021— including "pod," "bubble" and "breakthrough."

"Breakthrough is a word that has existed for hundreds of years in English," he said. "But now we use it to refer to an infection occurring in someone who is fully vaccinated against an infectious agent, as in ‘breakthrough cases’ or ‘breakthrough infections.’"

But it wasn’t all about the coronavirus in 2021. A number of terms that reflect the zeitgeist were added, too, including “cancel culture,” “gig worker” and the acronym "BIPOC."

Acronyms, and their cousins initialisms, have increasingly made their way into the dictionary. Initialisms are similar to acronyms, but rather than the letters being pronounced as a word, like LASER or SCUBA, each letter is pronounced, like two new entries in 2021: TBH — to be honest, and FTW — for the win.

The trend of technology inspiring new entries also continued in 2021. Terms added include “deplatform” — to remove and ban (a registered user) from a mass communication medium (such as a social networking or blogging website), and “digital nomad” — someone who performs their occupation entirely over the internet while traveling.

"There’s also the term 'bitrot,'" said Sokolowski. "So, digital culture has come so far in the last 20 to 30 years that we’re now talking about the erosion or degradation of digital culture. Bitrot: the tendency for digital information to degrade or become unusable over time."

Food words are also often a big driver of new dictionary entries. And a culinary term near and dear to many here in Massachusetts since at least 1960, when it was first trademarked, was finally added in 2021: That magical concoction of peanut butter and marshmallow once dubbed the "liberty sandwich" but today known the world over as the "fluffernutter."

Each year, the folks at Merriam-Webster select a “word of the year,” and Sokolowski said there were a few candidates in 2021. The word “insurrection” saw an extraordinary surge of interest in January — a 60,000% increase in lookups over the same time period in 2020.

Another contender was the word "infrastructure," a topic hotly debated in the halls of Congress for much of the year.

"The debates often were about the definition," said Sokowski. "They were about what infrastructure is. Does it include broadband, does it include medical care? Does it include childcare?"

Merriam-Webster defines it as "the basic equipment and structures (such as roads and bridges) that are needed for a country, region, or organization to function properly."

Despite the fact that it’s comprised of two Latin root words, infrastructure is a thoroughly modern term, coined by NATO and U.S. military forces as they led a rebuild of Europe following World War 2. In that sense, it's always been a political term.

"That term was then brought back to the United States to talk about the domestic agenda of President [Dwight] Eisenhower who was in the process of building our Interstate Highway System," explained Sokolowski.

But in the end, Sokolowski said the word of the year was always clear; one that saw record online traffic throughout the year and totaled more than a billion lookups: "vaccine."

"In the case of vaccine, we actually have a double story," said Sokowski. "There’s the medical story of the innovations and the mRNA vaccines for this particular coronavirus. But then there’s the second story, which is about mandates, about politics, really."