hydro-

CIDE DICTIONARY

hydro-,  

•  A combining form from Gr. Hydra).  [1913 Webster]
•  A combining form of hydrogen, indicating hydrogen as an ingredient, as hydrochloric; or a reduction product obtained by hydrogen, as hydroquinone.  [1913 Webster]

OXFORD DICTIONARY

hydro-, comb. form (also hydr- before a vowel)
1 having to do with water (hydroelectric).
2 Med. affected with an accumulation of serous fluid (hydrocele).
3 Chem. combined with hydrogen (hydrochloric).

Etymology

Gk hudro- f. hudor water