What does aquae mean?
Aquae is the plural form of aqua, the Latin word for water that English has borrowed directly. While aqua survives in modern English as a standalone term — appearing in phrases like 'aqua regia' and on color swatches — its plural aquae is far rarer, surviving mainly in pharmaceutical, alchemical, and historical texts, where it denotes multiple aqueous preparations or medicinal waters. Latin plurals of this kind were long standard in scientific nomenclature, and aquae appears in older pharmacopoeias listing distilled waters such as rose water or lavender water. The word carries a distinctly learned, archaic flavor: encountering it usually signals a classical, medical, or technical context. It belongs to the large family of English words descended from the Latin root aqua-, including aquatic, aquarium, and aqueduct, all of which preserve the ancient association with water.
nounThe plural of aqua; in English chiefly used in pharmaceutical and technical contexts to denote multiple aqueous preparations or medicinal waters.
- Plural of aqua: multiple waters or aqueous (water-based) preparations, especially in pharmaceutical and historical medical texts.
"The old pharmacopoeia listed several aquae, each prepared by distilling herbs in purified water."
"The apothecary's ledger recorded the aquae he distilled each spring from local herbs."
"Classical Roman engineers channeled the aquae of distant hills into the city's fountains."
Aquae is itself a plural form (the plural of aqua) and does not take a further plural; it retains the Latin plural rather than an anglicized '-s' ending.
"The text distinguished between simple and compound aquae according to their method of preparation."
Aquae is a living piece of Latin: pharmacists were still writing this ancient Roman plural on medicine labels well into the modern era.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of aquae
Aquae comes directly from Latin aqua ('water'), whose plural in classical Latin was aquae. English adopted both forms through scholarly and scientific borrowing, particularly in pharmacy and chemistry, where Latin nomenclature remained standard for centuries. The same Latin root gives English its many aqua- cognates, such as aquatic, aquarium, aqueduct, and aquamarine.
Related word forms
How aquae is actually used
Rare outside scholarly, historical, and pharmaceutical writing; in everyday English 'waters' or simply the plural of the borrowed term is used. Retains its Latin form rather than being anglicized.
Easily confused with aquae
Aqua is the singular form denoting one water or aqueous preparation, while aquae is its plural, denoting several such waters.