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Beat the Board
1. In community card games - to make a hand of higher rank than a hand consisting solely of the community cards, especially when the community cards represent a hand of relatively high value such as a straight or flush.
"The board was 4h-8h-9h-Qh-Jh, making a Queen-high hearts flush. I had Kh in the pocket so I beat the board with a higher flush." 

2. In stud games - to make a hand higher than a hand consisting solely of any opponent's exposed cards.
 
Australian Poker Weekly