Researchers behind the renowned dictionaries pick a prominent word or expression in the English language each year that best reflects the mood of the times. Previous words of the year have included "unfriend" in 2009, "credit crunch" in 2008, "carbon footprint" in 2007 and "Sudoku" in 2005.
Judy Pearsall, the editorial director for Oxford Dictionaries, said "selfie" appeared to have been first used in 2002 on an Australian online forum, and the hashtag #selfie appeared on the photo-sharing website Flickr in 2004.
"But usage wasn't widespread until around 2012, when 'selfie' was being used commonly in mainstream media," she said.
Australian English sometimes uses the suffix "-ie" — such as barbie for barbeque and tinnie for a can of beer — which helps to explain where "selfie" may have come from, Pearsall added.
Oxford usually assigns a separate word of the year to the U.S. and to the U.K., but it said "selfie" captured the imagination on both sides of the Atlantic this year.
The term beat other buzzwords including "twerk," the sexually provocative dance move that got a huge boost in usage thanks to an attention-grabbing performance by pop star Miley Cyrus; "showrooming," the practice of visiting a shop to look at a product before buying it online at a lower price; and "Bitcoin," the digital currency that gained widespread media attention.
Also making the shortlist was "binge-watch," a verb that describes watching many episodes of a TV show in rapid succession.
The words were chosen by a research program that monitors online content and collects around 150 million words of English in use each month.
"Selfie" was added to the online version of the Oxford dictionary in August and is being considered for future inclusion in the more traditional Oxford English Dictionary.