al·ka·line \ˈalkələ̇n, -ˌlīn\adjective Etymology:alkali + -ine 1.: of, relating to, or having the properties of an alkali: as a.: having an alkaline reaction : having a pH of more than 7 < an alkaline soil > < a strongly alkaline solution > b.: containing or involving the use of alkali < alkaline bath > < alkaline fusion > — see basic 3, caustic 1 2.: of or relating to the alkali metals