Hand is a gambling term used to refer to the cards the player is holding in their hand, and the origin of the term is self-explanatory.
In some cases, players also refer to every fresh round of poker or blackjack, for example, as a hand. Therefore, if someone says they are going to play only ten hands, it means they are only staying there for a while.
In addition, if they are asking to see your hand, they are curious about the cards you are holding.