A stroke of luck; a fortunate event, particularly of the sort that propels one to success, fame, etc.
The ratio of winnings to stake in betting situations.
The ratio of the probability of an event happening to that of it not happening.
I'd say the odds are strongly in favor of the sun rising tomorrow morning.
An advantage given to a weaker opponent in order to equalize the game when playing casually, usually by removing one of the stronger player's pieces or by giving the weaker player more time.