There's the ocassional exception to the rule, but generally online slot machines are either 3 reel. or 5 reel. machines. Classic, 3 reel slots. These are what's generally considered 'regular' slot machines - 3 reels with symbols spin around, stop one at a time, and winning combinations are paid to the player after each spin is complete. 5 Reel slots. These are simlpy slot machines with 5 reels instead of 3. Same concept as a 'regular' slot machine, except there are few if any 5-reel machines with only one payline, (see below) and there are generally winning combinations that pay off with less than 5 matches. (3 symbols on a payline might pay off a lower amount even though there's 4 and 5 symbol matches on the paytable as well for example). .