The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
wed-1
DEFINITION:
Water; wet. Derivatives include water, hydrant, redundant, otter, and vodka. 1. Suffixed o-grade form *wod-r.a.water, from Old English wæter, water; b.kirschwasser, from Old High German wassar, water. Both a and b from Germanic *watar.2. Suffixed lengthened-grade form *wd-o-.wet, from Old English wt,wt, wet, from Germanic *wd-.3. O-grade form *wod-.wash, from Old English wæscan,wacsan, to wash, from Germanic suffixed form *wat-skan, to wash. 4. Nasalized form *we-n-d-.winter, from Old English winter, winter, from Germanic *wintruz, winter, wet season. 5. Suffixed zero-grade form *ud-r.hydrant, hydro-, hydrous, utricle; anhydrous, clepsydra, dropsy, hydathode, hydatid, from Greek hudr, water. 6. Suffixed nasalized zero-grade form *u-n-d--.undine, undulate; abound, inundate, redound, redundant, surround, from Latin unda, wave. 7. Suffixed zero-grade form *ud-ro-,*ud-r-, water animal. a.otter, from Old English otor, otter, from Germanic *otraz, otter; b.nutria, from Latin lutra, otter (with obscure l-); c.Hydrus, from Greek hudros, a water snake; d.Hydra, hydrilla, from Greek hudr, a water serpent, Hydra. 8. Suffixed zero-grade form *ud-skio-.usquebaugh, whiskey, from Old Irish uisce, water. 9. Suffixed o-grade form *wod--.vodka, from Russian voda, water. (Pokorny 9. a(e)- 78.)