ANTIAC'ID, adjective Opposing or removing acidity. Often written antacid. ANTIAC'ID, noun An alkali; a medicine proper to correct sourness, or acidity; an absorbent, as chalk, magnesia, coral, sea shells, hematite, steel fillings; or an obtundent, as oil or fat; or an immutant, as lixivious salts, and soaps.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI