Gambling is the wagering of money or something of material value (referred to as "the stakes") on an event with an uncertain outcome with the primary intent of winning additional money and/or material goods. Typically, the outcome of the wager is evident within a short period.

The term gaming^[1] in this context typically refers to instances in which the activity has been specifically permitted by law. The two words are not mutually exclusive; i.e., a “gaming” company offers (legal) “gambling” activities to the public^[2] and may be regulated by one of many gaming control boards, for example, the Nevada Gaming Control Board. However, this distinction is not universally observed in the English-speaking world. For instance, in the UK, the regulator of gambling activities is called the Gambling Commission (not the Gaming Commission).^[3] Also, the word gaming is frequently used to describe activities that do not involve wagering, especially online.

Gambling is also a major international commercial activity, with the legal gambling market totaling an estimated $335 billion in 2009.^[4] In other forms, gambling can be conducted with materials which have a value, but are not real money. For example, players of marbles games might wager marbles, and likewise games of Pogs or Magic: The Gathering can be played with the collectible game pieces (respectively, small discs and trading cards) as stakes, resulting in a meta-game regarding the value of a player's collection of pieces.