'refill' originates from a combination of Latin and Old English, specifically the Latin prefix 're-' and the Old English word 'fyllan', where 're-' meant 'again' and 'fyllan' meant 'to fill'.

'fill' changed from Old English word 'fyllan' to Middle English 'fillen' and eventually became the modern English 'fill'; the modern word 'refill' was formed by adding the prefix 're-' to 'fill' in Modern English.

Initially, it meant 'to fill again', and over time it has retained this core sense of 'filling or supplying again' in modern usage.