Meaning of ALKALI in English

al ‧ ka ‧ li /ˈælkəlaɪ/ BrE AmE noun [uncountable and countable]

[ Date: 1300-1400 ; Language: Medieval Latin ; Origin: Arabic al-qili 'the ashes (of a particular plant from which a type of alkali was obtained)' ]

a substance that forms a chemical salt when combined with an acid ⇨ acid

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.