'bandwagon' originates from American English, specifically the compound word 'bandwagon,' where 'band' meant 'a group of musicians' and 'wagon' meant 'a wheeled vehicle.'

'bandwagon' originally referred to the wagon that carried a musical band in parades and circus processions in the mid-19th century United States, and the term later developed a figurative sense referring to something that attracts popular support.

Initially, it meant 'a wagon carrying a band,' but over time it evolved into the current meaning of 'a popular cause/trend that many people join or support.'