Big world events often influence how much a word is looked up online, and Merriam-Webster’s most searched terms of 2021 make up their Word of the Year list. For 2021, the top word on the list was — surprise, surprise — ”vaccine.”
According to Merriam-Webster, interest in the word rose a lot since 2019: “lookups for vaccine increased 601% year-over-year from 2020. But interest in the word has been high since the start of the COVID-19 pandemic, with much discussion of the funding, development, testing, and ultimate distribution of the vaccines occurring in 2020. The prominence of the word vaccine in our lives in this era becomes even more starkly clear when we compare 2021 to 2019, a period in which lookups for the word increased 1,048%.”
The definition of vaccine was revised and expanded in May 2021:
The definition, which formerly read “a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease,” was replaced with the following:
1 : a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease: such as
a : an antigenic preparation of a typically inactivated or attenuated (see ATTENUATED sense 2) pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin)
b : a preparation of genetic material (such as a strand of synthesized messenger RNA) that is used by the cells of the body to produce an antigenic substance (such as a fragment of virus spike protein)
There were other highly relevant words on the list, too: “insurrection,” “perseverance,” “woke,” “nomad,” “infrastructure,” “cicada,” “murraya,” “cisgender,” “guardian,” and “meta.” You can read more about each of them here.
The 2020 word of the year was “pandemic,” and the theme has not changed much since.