'gratuity' originates from Latin, specifically the word 'grātuitās' (from 'grātuitus'), where 'grātus' meant 'pleasing, thankful'.

'gratuity' changed from Latin 'grātuitās' to Old French 'gratuité' and Middle English forms such as 'gratuyte', eventually becoming the modern English word 'gratuity'.

Initially, it meant 'a favor or gift given freely'; over time it evolved to mean 'a voluntary payment given in return for a service' and later also 'a bonus or allowance (e.g., on retirement)'.