alkali
noun
[ ˈalkəlʌɪ ]
• a compound with particular chemical properties including turning litmus blue and neutralizing or effervescing with acids; typically, a caustic or corrosive substance of this kind such as lime or soda.
• "flint is not subject to chemical weathering except by strong alkalis"
Origin:
late Middle English (denoting a saline substance derived from the ashes of various plants, including glasswort): from medieval Latin, from Arabic al-qalī ‘calcined ashes (of the glasswort etc.)’, from qalā ‘fry, roast’.
