I've always thought of gambling to be an activity that would involve you staking some amount of money. If there is no stake really, calling it gambling becomes difficult.
to me anything that you own that you would hate to lose can be staked in gambling
we see often times people tend to put their cars, houses, jewelry on the line when they are gambling this is what makes it gambling for me the risk of losing valuable assets but the chance of winning more and having more than you first started