I was holding an ace in my hand during an Omaha game. There were four clubs on the board. Why did I lose this hand?
In Omaha Hold'em you have to use exactly two of the four cards from your hand and three on the board (since a poker hand is exactly five cards).
This means you can only have the flush when you have two cards of the same suit in your hand and there are at least three cards of that suit on the board.