'numerous' originates from Latin, specifically the word 'numerosus', where 'numerus' meant 'number' and the suffix '-osus' meant 'full of'.

'numerosus' changed into Old French (e.g. 'nombreus'/'nombreux') and then entered Middle English as 'numerous', eventually becoming the modern English word 'numerous'.

Initially, it meant 'full of numbers' or 'having numbers', but over time it evolved into its current meaning of 'existing in large numbers' or 'many'.