'balloon' originates from French, specifically the word 'ballon', which in turn comes from Italian 'ballone', where 'balla/ballo' (from Latin 'pālla' / 'palla') meant 'ball'.

'balloon' changed from Italian 'ballone' to French 'ballon' and was adopted into English in the late 16th century; the verb and the noun sense related to inflated bags and flying devices developed later, and 'ballooning' as the activity (hot-air balloon flight) emerged in the 18th–19th centuries.

Initially it meant 'a large ball' or 'round object'; over time it came to mean 'an inflated bag' and then 'to become inflated' or 'to increase rapidly', and finally the noun sense 'the activity of flying in a balloon'.