According to Britannca definition, gambling is said to be  the betting or staking of something of value, with consciousness of risk and hope of gain, on the outcome of a game, a contest, or an uncertain event whose result may be determined by chance or accident or have an unexpected result by reason of the bettor's miscalculation.
 Therefore whether it involves staking money or not so far it requires you to make predictions about an event then it's also considered as gambling however apart from online casino, money is not the only requirement for staking on games or events, in rural areas most people who play draft stake their valuable items over who would win the game.