'tallier' originates from English, specifically the word 'tally' + suffix '-er', where 'tally' meant 'a mark (a notch) used for counting' and '-er' meant 'one who (agent)'.

'tally' changed from Old French (such as 'tailler' / 'taillier', meaning 'to cut' or 'to notch') referring to notches cut on a stick for counting; this became the English noun 'tally', and adding the agent suffix '-er' produced the noun 'tallier' meaning 'one who tallies'.

Initially, it meant 'a notch or mark used for counting', but over time it evolved into its current sense of 'a record or count' and, by extension, 'one who counts or records'.