an informal noun (plural: selfies) defined as “a photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website.” It was first used in 2002, in an Australian online forum (compare the Australian diminutives “barbie” for barbecue and “firie” for firefighter), and it first appeared as a hashtag, #selfie, on Flickr, in 2004
…dubbed the word of the year by The New Yorker, and officially included in the Oxford Dictionary Online.
Also worth noting, the difference between the Oxford Dictionary Online, and the Oxford English Dictionary:
reflects current and practical usage; it’s the liberal and inclusive descriptivist dictionary, and is frequently updated. It demonstrates the language as it’s being used today, much like Joe Toscano’s Twitter bot, @tofu_product, imitates your Twitter voice by using an algorithm that reads your most recent two hundred or so tweets (“Tofu absorbs flavor. I write like you do,” reads its bio).
a historical document that relies heavily on quotations and chronology as evidence for the development of meaning over time. Words can be removed from the O.D.O. after they stopped being used, but words are never (really) removed from the O.E.D.