Posca
Posca vinegar mixed with water, was the common drink of the lower orders among the Romans (Suet. Vitell. 12), of slaves (Plaut. Mil. 3.2, 23), and of soldiers on service (Spart. Hadr. 10). As to the theory that the celebrated acetum of Liv. 21.37 was posca (see Capes ad loc.), it is well known that some rocks, as limestone, can be split by any cold liquid poured over them when they are hot, and so more easily cut into a roadway (see Blümner, Technol. 3.71). Hennebert (Annibal, ii. p. 253; Paris, 1878) tries elaborately to establish an explosive property for some composition called ὄξος or acetum.
From William Smith (ed.), Dictionary of Greek and Roman Antiquities. Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities and Tufts University. Data accessed from https://github.com/PerseusDL/canonical-pdlrefwk/ on 17 October 2026.