'Britishism' originates from English, specifically from the word 'British' with the suffix '-ism', where 'British' refers to things of or relating to Britain, and '-ism' denotes a distinctive practice, system, or philosophy.

'Britishism' was formed in the 19th century by combining 'British' and the suffix '-ism', and eventually became the modern English word 'Britishism'.

Initially, it meant 'a characteristic feature of British English', and this meaning has remained consistent in modern usage.