carbonate UK /ˈkɑː(ɹ).bə.neɪt/US /ˈkɑɹbəneɪt/noun 1verb 1forms 3 noun1 •Any salt or ester of carbonic acid.A sample of carbon removed from the ocean in the solid form of calcium carbonate and magnesium hydroxide from UCLA's SeaChange program -- now known as Equatic -- in 2023. — 2024 verb1 •To charge (often a beverage) with carbon dioxide. formscarbonated · carbonating · carbonates