One of the broadest definition of online casino games could be those games that involve an element of chance and are played between the players and the house, and not among players themselves. Some games involve both skill and chance like blackjack, video poker, whereas others involve only chance like slots, roulette and keno.
Online casino games are characterized by an average payout ratio. The average pay out ratio is defined as the amount of money that the online casinos for real money pays out on an average per dollar wagered expressed as a percentage. The average payout ratio is governed by the software developed based on the rules of the game. Once the software is frozen then the average payout ratio is independent of any decision made by the player.
In online casino games that involve some skill the average payout ratio assumes that the player makes the optimal decisions. In these games the player can increase his chances of winning up to the average payout ratio by learning how to play casino game optimally. However in those online casino games that depend on chance alone, there is nothing that the player can do to improve his chances of winning.