Merriam-Webster added 455 words to the dictionary this month, including four that have gained prominence during the COVID-19 pandemic.
The four pandemic-related words that were added are "breakthrough," "super-spreader," "long COVID" and "vaccine passport."
The new additions come after "long-hauler," "pod" and "bubble" were added to the dictionary in January, alongside 517 other words.
In December 2020, Merriam-Webster also selected "pandemic" as the 2020 word of the year.