D-E-TH – ‘to ken (both inner essence and outer form)

דע is a root which contains every idea of exposition, explanation, demonstration; being formed by contraction of the roots יד the hand, that which shows, and צע the superficies, the curve, the exterior form of things.

…Thus, knowledge, indicated by the Hebrew text, is that which depends upon judgment and upon exterior forms…The word knowledge and the Greek γνωσις [gnosis] are derived from the Celtic word ken or kan, which signifies to conceive, to comprehend, to embrace in a glance, etc. (The Hebraic Tongue Restored, Fabré d’Olivet, p. 84-85)