A bet or wager.
I had a gamble on the horses last weekend.
A significant risk, undertaken with a potential gain.
A risky venture.
The sailors had taken many gambles with the sea and always won.
To take a risk, with the potential of a positive outcome.
To play risky games, especially casino games, for monetary gain.
To risk (something) for potential gain.
He gambled his reputation on the outcome.
To interact with equipment at a casino