Definition of scooping a pot
Some poker games, such as Hold'em, are high stakes games. By high we mean that players must make the best possible hand. At the showdown, the player who wins the pot will be the one with the best hand, the strongest hand. But some variants like Omaha High-Low will have the pot split in 2; 50% of the pot for the highest hand and 50% of the pot for the lowest hand. If you win both the high and low (both pots) on the showdown of an Omaha High-Low hand, you are said to have scooped the pot.
An example of a scooped pot
You are on the button in a game of Omaha High-Low. You have A-A-2-3 over A-K-5-6-9. Your opponent has K-K-3-4. Since there are 3 low cards on the board, the low will be played (A-5-6). For the high, you will win 50% of the reserved pot because you beat his three of a kind with your three of a kind ace. And with your 23 in hand, you have the best low for A-2-3-5-6. Your opponent has a slightly worse low of A-3-4-5-6. You win both halves of the pot and scoop the pot!