Odds
The probability of making a hand versus the probability of not making the hand.
Offsuit
A holdem starting hand in which the two cards are of different suits.
Omaha
A flop game similar to Holdem, but each player is dealt four cards instead of two, and a hand must be made using exactly two pocket cards, plus three from the table.
On Board
On the table; in the game.
On The Come
A hand that is drawing to a straight or flush.
On Tilt
Playing poorly, usually because of becoming emotionally upset.
One-Gap
A holdem starting hand in which the two cards are two apart in rank. Examples: J9s, 64.
One-Gap
An inside straight.
Open Card
Exposed card; a card dealt face-up.
Open Ended Straight
Four consecutive cards whereby one additional (consecutive) card is needed at either end to make a straight.
Open Pair
An exposed pair; a pair of face-up cards.
Open Poker
Games where some of the cards are dealt face up.
Open
To make the first bet in a round.
Open-Ended Straight Draw
A straight draw with four consecutive cards that can be completed on either end. An example is 6/7/8/9, since a five or a 10 will make a straight.
Open-Ended Straight
Four consecutive cards requiring one at either end to make a straight.
Option
If no one raises the big blind, then the player in that position has the option to raise when their turn comes around. The dealer will typically say something like 'your option,' to remind them.
Out
A card remaining in the deck that could hopefully improve your hand.
Out
A card that will make your hand win. Normally heard in the plural. Example: 'Any spade will make my flush, so I have nine outs.'
Outdraw
To beat an opponent by drawing to a better hand.
Outrun
To beat. Example: 'Susie outran my set when her flush card hit on the river.'
Over Button
A type of button that indicates you are willing to play at higher limits. Any time everyone left in the hand has an over button, the limits go up.
Overcall
To call a bet after one or more others players have already called.
Overcard
A card higher than any card on the board. For instance, if you have AQ and the flop comes J-7-3, you don't have a pair, but you have two overcards. | 
