(inorganic chemistry) An oxide of an element of group 2 in the periodic table, such as barium, calcium, and strontium. Also known as alkaline-earth oxide.
alkaline earths (ăl'kəlīn, -lĭn), oxides of the alkaline-earth metals, especially of calcium, strontium, and barium. They are not readily soluble in water and form solutions less basic than those of alkalies.