'frankfurter' originates from German, specifically the word 'Frankfurter', where 'Frankfurt' referred to the city of Frankfurt (literally 'ford of the Franks').

'frankfurter' entered English from German (as 'Frankfurter') in the 19th century; the term originally denoted something or someone from Frankfurt and later was applied to the sausage associated with that city, becoming the English word 'frankfurter'.

Initially, it meant 'a person or thing from Frankfurt'; over time it evolved to mean specifically 'a sausage from Frankfurt' and, by extension, the hot dog-style sausage used in sandwiches.