An acronym(from Greek ἄκρος, akros ‘, high, end, tip’ and ὄνομα, onoma ‘name’, “is a word formed usually with the initials of others whose meaning corresponds to the meanings of initial words. SPA is an acronym.
SPA is an acronym of undoubted fortune. To this union of three initials incumbent numerous combinations of words, some so curious and crazy as that which says they are the initials of the names of three great ancient philosophers Socrates, Plato, Aristotle.
The “Acronyms, Initialisms & Abbreviations Dictionary (2000)” provides a list of 187 acronyms meanings for these three letters; naturally not includes a reference to the three ancient Greek philosophers. But is collected an explanation which has made a fortune and has certainly relationship with the Roman world. Is usually interpreted in many contexts as Salutem per Aquam = to health by water and even as Sanus per Aquam.
Certainly this interpretation falls on fertile ground because the importance of water and its use in the Roman culture in general and urban planning in particular. Marshes, aqueducts, fountains, baths are inseparable elements of the Roman urbs. The baths or thermae, a Latin word derived f from θερμός Greek (thermos = hot), are an essential element in Roman urban life, are the social meeting point of the idle Roman citizens. Naturally, all wealthy Roman live in luxury houses in them can not miss the hot water, about which we'll talk another time.
Moreover, the hot springs or sulphurous water always had a special attraction, magical and religious also, for men, certainly they had it for the Romans, who found them and used there where they found them. Moreover, perfectly differed medicinal springs from normal water supply.
Some cities were created around these enclaves, are famous in Europe Baden Baden in Germany and Bath in England. Both words mean precisely "the baths". The Roman name of German was Aquae Aureliae (Waters of Aurelius), the name of the British was Aquae Sulis (Waters of Sulis, the name of a goddess).
There are also numerous cities called Caldas, evident name from Aquae Calidae, Hot Waters.
We can add some bath cities more than the above as significant examples spread across Europe: Aquae Sextiae (Aix-En-Provence, France) – Aquae Gratianae (Aix-les-Bains, France); Aquae Pannonicae, (Baden, Austria), Aquae Helveticae (Baden, Switzerland); Aquae Bigerriorum (Bagneres-De-Bigorre, France); Aquae Urentes , (Orense, Hispania); Aquae Calidae, (Vichy, France), Aquae Mattiacae, (Wiesbaden, Germany).
But there is a place of particular interest to this article called the Aquae Sepadonae in Middle Age, and in modern time Aquae Spadanae which corresponds to the present city of Spa in Belgium.
So the quoted acronym SPA found in the Roman world the culture broth to be interpreted as Salutem per Aquam. The problem is that there is not a reference in the ancient world to the phrase as such nor the content or concept of water as a means to health.
Instead, there it is reference from antiquity to the mentioned Belgian city in the province of Liege, called SPA precisely known since then by its hot baths, by its hot springs, which then in modern and contemporary time has been a recognized place to take the waters and enjoy a good rest, among others by the English who have spread the name around the world to such establishments.
Pliny the Elder gives us information in his encyclopaedic Naturalis Historia, in the XXXI book precisely about water, in chapter 12 gives reference to a city or a tribe of Gaul, the Tungros in the Ardennes of Belgium, precisely where today is the city Spa.
He says in Naturalis Historia, XXXI, 8 (12):
The state of the Tungri, in Gaul, has a spring of great renown, which sparkles as it bursts forth with bubbles innumerable, and has a certain ferruginous taste, only to be perceived after it has been drunk. This water is strongly purgative, is curative of tertian fevers, and disperses urinary calculi: upon the application of fire it assumes a turbid appearance, and finally turns red. (Pliny the Elder, The Natural History, John Bostock, M.D., F.R.S., H.T. Riley, Esq., B.A., Ed.)
Tungri civitas Galliae fontem habet insignem plurimis bullis stillantem, ferruginei saporis, quod ipsum non nisi in fine potus intellegitur. purgat hic corpora, tertianas febres discutit, calculorum vitia. eadem aqua igne admoto turbida fit ac postremo rubescit.
As mentioned, in the medieval sources this city is known as AQUAE SEPADONAE and in modern times AQUAE SPADANAE.
In turn, this spring has led to considerer as the origin of the name of the city SPA itself the latin verb spargere and its form sparsa which means sprout, spread. But it seems more probable that the name is originally Nordic or Germanic; actually exists the term "spa" with some variation in some Nordic languages, but its meaning has nothing to do with hot water or medicinal but with prophecy, prediction.
It could be related to the word spa or old spaw which in Walloon language means source and is still used in the north of Britain (Yorkshire) as synonymous with spa, but I have this issue not well documented.
The Oxford English Dictionary (OED gives four definitions of Spa, from the earliest reference to the occurrence of the word in England in 1565 to use in the United States today.
The place was as famous in the ancient Roman world and in the Middle Ages and especially became fashionable as a place to take the waters from the seventeenth century between the British and the wealthy men in Europe, here was for example the future Tsar Peter the Great in 1717 during his stay in the Netherlands to study the levees that contained the sea. The British took it to United States and to the rest of the world, where it has established itself with the meaning of spa, where to take baths or hot springs or medicinal waters.
Consequently the toponym SPA, name of the town in Belgium where he had a hot springs well known and appreciated since ancient times, has come to mean a generic "spa, hot springs, hot springs, healing waters". It was suggestive explanation of "salutem per aquam" precisely because of its explanatory power, but we can consider it a one backronym or acronym subsequently manufactured leveraging the Roman tradition of interest in medicinal quality water of the city SPA in Belgium.