'ballgown' originates from English, a compound of 'ball' (an occasion for dancing) + 'gown' (a long outer garment or robe).

'ball' comes from Old French 'bal' (from Late Latin 'ballare', to dance) and 'gown' comes from Old French 'goune' / Medieval Latin 'gunna' meaning a robe; the compound 'ball gown' (often written as two words) arose in English in the 19th century to name the formal dress for a ball and later appears as the single-word form 'ballgown'.

Initially it referred simply to a 'robe or dress worn to a ball'; over time it became specialized to mean a formal, often full-skirted evening dress worn at balls or similar formal events.