'scheduler' originates from Modern English composition: the noun 'schedule' plus the agentive suffix '-er', where the suffix '-er' meant 'one who (performs an action)'.

'schedule' itself comes from Old French/Anglo-French forms such as 'schedule'/'cedule' and ultimately from Late Latin 'schedula' (a small slip of papyrus), which in turn derives from Greek roots referring to a strip or slip of paper; the agentive '-er' was added in English to form 'scheduler'.

Originally related to a 'small slip of paper' or list (from Latin 'schedula'), the word 'schedule' shifted to mean a plan or timetable; 'scheduler' then developed to mean 'one who makes or manages that timetable' and later extended to devices/programs that perform scheduling.