noun, plural al·ka·lis, al·ka·lies.
- any of various bases, the hydroxides of the alkali metals and of ammonium, that neutralize acids to form salts and turn red litmus paper blue.
- any of various other more or less active bases, as calcium hydroxide.
- (not in technical use) an alkali metal.
- Obsolete.any of various other compounds, as the carbonates of sodium and potassium.
- Agriculture. a soluble mineral salt or a mixture of soluble salts, present in some soils, especially in arid regions, and detrimental to the growing of most crops.
- Chemistry. alkaline.
noun plural -lis or -lies
- chem a soluble base or a solution of a base
- a soluble mineral salt that occurs in arid soils and some natural waters
late 14c., “soda ash,” from Medieval Latin alkali, from Arabic al-qaliy “the ashes, burnt ashes” (of saltwort, a plant growing in alkaline soils), from qala “to roast in a pan.” The modern chemistry sense is from 1813.
n. pl. al•ka•lis
- A carbonate or hydroxide of an alkali metal, the aqueous solution of which is bitter, slippery, caustic, and characteristically basic in reactions.
- Any of various soluble mineral salts found in natural water and arid soils.
- Alkali metal.
Plural alkalis alkalies
- A hydroxide of an alkali metal. The aqueous solution of alkalis is bitter, slippery, caustic, and characteristically basic in reactions.