/ ˈælkəlaɪ; NAmE / noun
[ C , U ] ( chemistry ) a chemical substance that reacts with acids to form a salt and gives a solution with a pH of more than seven when it is dissolved in water
—compare acid
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WORD ORIGIN
late Middle English (denoting a saline substance derived from the ashes of various plants, including glasswort, a salt-marsh plant formerly used to make glass): from medieval Latin , from Arabic al-qalī calcined ashes (of the glasswort etc.), reduced through exposure to strong heat, from qalā fry, roast.