'reward-based' originates from the combination of 'reward' and 'based', where 'reward' meant 'a thing given in recognition of service, effort, or achievement' and 'based' meant 'having as a foundation'.

'Reward' comes from the Old French word 'reguard', and 'based' comes from the Middle English word 'basen'.

Initially, 'reward' meant 'regard or consideration', but over time it evolved into its current meaning of 'a thing given in recognition of service, effort, or achievement'.