The style of game is known as "diceless" because most games use dice as their randomiser; some games such as Castle Falkenstein use other randomisers such as playing cards as substitutes for dice, and are not considered "diceless".
The style of game is known as "dice-free" because most games use dice as their randomizer; some games, such as Castle Falkenstein, utilize other randomizers like playing cards in place of dice and are not considered "dice-free".