The editors of the Merriam-Webster dictionary would like you to know that “cougar” doesn’t just refer to an animal. It can also invoke a “middle-aged woman seeking a romantic relationship with a younger man.”
That’s just one of the 150 new entries included in the dictionary’s 2011 edition. Wordsmiths at the dictionary also added “bromance” (a close, non-sexual relationship between men), “helicopter parent” (a parent who is overly involved in the life of his or her child) and “boomerang child” (a young adult who returns to live at his or her family home especially for financial reasons).
Editors at the Springfield, Mass.-based lexicon say that usage is the central criteria for inclusion. Words that meet a certain threshold of usage in major media outlets make a shortlist, which editors then whittle down based on importance and relevance. Readers will already recognize many of the entries, even if these words only recently received enough media attention to merit their inclusion. They include “Americana,” which describes the musical genre with roots in early folk and country music, and “fist bump,” a knuckle-knocking gesture that connotes affection and respect, much like a handshake. The latter term received a flurry of attention after Barack and Michelle Obama bumped fists as he took to the stage to claim the 2008 Democratic presidential nomination in St. Paul, Minn.
Entries related to the Internet include “crowdsourcing”—the practice of obtaining information from a large group of people who contribute online—and “tweet.”
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“From the dramatic events of the Arab Spring to the scandal that brought down Congressman Anthony Weiner, ‘tweet’ is a word that has been part of the story,” says Peter Sokolowski of Merriam-Webster. “Even if people had no interest or possible chance of getting a Twitter account themselves, they now have to know what ‘tweet’ means, and that’s really why it’s in the dictionary.”
Words that are perhaps less obvious to most users include “parkour,” a sport that combines running, climbing and leaping over environmental obstacles, and “m-commerce,” business transactions carried out using mobile devices.
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William Lee Adams is a staff writer at the London bureau of TIME. Find him on Twitter at @willyleeadams or on Facebook. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.