American Heritage Dictionary
(4)
Century Dictionary
GNU Webster's 1913
WordNet
(3)
Elsewhere on the web
It's perfect music for cocktail hour -- upbeat, soulful and sexy ...— Cool Hunting
It finds TVOTR wisely offering an early pace shift to the album -- upbeat, but not as unbridled as the opener -- because this is where Tunde jumps into the speedy enunciation of "Dancing Choose" (and its mellow-ass "In my mind I'm counting butterflies" chorus).— Stereogum
Around me were all types of people -- upbeat, enthusiastic, COLD, but ready to see the soon to be #44!— Blog updates
But we recently met a young man who has stayed upbeat, and positive even through a life-changing accident.
D.C. And we head into this new week with the president whose tone is noticeably more upbeat, a stock market that saw its best run since November, four days of gains.— NewsBusters.org - Exposing Liberal Media Bias

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You can expect to see this word about twice a week.