'Spa' comes from Spa, Belgium — famous for mineral springs since medieval times. The acronym theory is false.
A place with mineral springs used for bathing and health treatments; a commercial establishment offering health and beauty treatments.
From Spa, a town in the province of Liège in eastern Belgium, famous since the fourteenth century for its mineral springs. The town name is of uncertain origin. One theory derives it from Walloon 'espa' (fountain, spring). A popular folk etymology treats 'SPA' as an acronym for Latin 'Sanitas
The town of Spa in Belgium is also famous as the home of the Spa-Francorchamps motor racing circuit, one of the most celebrated Formula 1 tracks. The mineral water brand 'Spa' (owned by Spadel) has been bottled from the town's springs since 1583. The claim that 'SPA' stands for 'Sanitas Per Aquam' is a modern invention