weH-d-
“to wash, to wet”wash, bathe
PIE root meaning to wash or to wet. Source of English "wash," "water" (extended), and words for cleansing with liquid.
Discussion
*weH-d- is a Proto-Indo-European root meaning "to wash" or "to wet," closely related to the fundamental water root *wed- "water."
The root gives Old English wæscan "to wash" (modern English wash) and wǣt "wet" (modern English wet). German waschen "to wash" and Wasser "water" show the close connection between washing and water in Germanic. The relationship to *wed- "water" is transparent—washing is the act of applying water.
Latin unda "wave" (whence English undulate, inundate, abundant—"overflowing") may derive from a related form. Greek hýdōr "water" (whence English hydro-, hydraulic, hydrogen) reflects the base *wed- root that underlies this extended form.
In Slavic, Russian voda "water" and Czech voda preserve the base form. Sanskrit udán- "water" and the river name Indus (from *Hwindus, related to *wed-) extend the family.
The semantic range encompasses both the substance (water) and the action (washing/wetting), suggesting these were not sharply distinguished in PIE. Modern descendants include English wash, wet, water, and through Greek and Latin: hydro-, undulate, inundate, and vodka (Russian, "little water").
Notes
Source of English "wash", "water". Extended from *wed- (water).