A combining form from Gr. /, /, water (see 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]
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).