It's a word that has been a part of the English language since the 1800s, according to the Associated Press, but use of and interest in the word has surged this year, hence it's recognition as Word of the Year by Dictionary.com.
The site defines xenophobia as "fear or hatred of foreigners, people from different cultures or strangers" and "fear or dislike of the customs, dress, etc. of people who are culturally different from oneself."
Online search for the word first spiked on June 24, the day after the UK voted to leave the European Union. Days later, search for the word spiked again, when President Barack Obama called Donald Trump's political rhetoric an example of "nativism or xenophobia" during a June 29 speech.
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Immigration policies, especially in regards to Syria's refugee crisis, police violence against people of color and transsexual rights have also been important issues in 2016.
"Xenophobia and other words tied to global news and political rhetoric reflected the worldwide interest in the unfortunate rise of fear of otherness in 2016, making it the clear choice for Word of the Year," Liz McMillan, CEO of Dictionary.com, said in a statement. "While we can never know the exact reasons why xenophobia trended in our lookups this year, this reflects a desire in our users to understand the significant discourse surrounding global events."
Dictionary.com, which has been naming a word of the year since 2010, chooses a word based on search data.
"I wish we could have chosen a word like unicorns," said Jane Solomon, one of the dictionary site's lexicographers.
"Dictionary.com is right to make xenophobia the word of the year, but it is also one of the biggest threats we face," said Robert Reich, professor at Berkeley's Goldman School of Public Policy. "It is not a word to be celebrated. It is a sentiment to be fought."
Oxford Dictionaries named their word of the year "post-truth."