'number-based' originates from Modern English compounding of 'number' and the past-participle/adjective form 'based' (from 'base'). 'number' ultimately comes from Latin 'numerus', where 'numer-' meant 'number, quantity'; 'base' comes via Old French/Latin/Greek (Latin/Greek elements meaning 'foundation').

'number' traces back to Latin 'numerus' and Old French forms before entering Middle English; 'base' comes from Old French and classical Latin/Greek 'basis'. The compound 'number-based' was formed in Modern English by combining these elements and became more common in the mid-to-late 20th century with the rise of statistical and data-driven discourse.

Initially the elements referred separately to 'a number' and 'a foundation'; over time the compound came to mean 'derived from or justified by numerical data' rather than merely 'having numbers'.