Entry 1 sense Webster, 1913 Alkahest /ăl'-kəh-ĕstˌ/ · Al·ka·hest · IPA /ˈal.kə.hɛst/ 01 n. The fabled “universal solvent” of the alchemists; a menstruum capable of dissolving all bodies. 1. The fabled “universal solvent” of the alchemists; a menstruum capable of dissolving all bodies.