- a combining form meaning “water,” used in the formation of compound words: hydroplane; hydrogen.
Also especially before a vowel, hydr-1.
Origin of hydro-1
< Greek, combining form of hýdōr water
- a combining form representing hydrogen in compound words, denoting especially a combination of hydrogen with some negative element or radical: hydrobromic.
Also especially before a vowel, hydr-2.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
sometimes before a vowel hydr-
- indicating or denoting water, liquid, or fluidhydrolysis; hydrodynamics
- indicating the presence of hydrogen in a chemical compoundhydrochloric acid
- indicating a hydroidhydrozoan
from Greek hudōr water
Word Origin and History for hydro-
Online Etymology Dictionary, © 2010 Douglas Harper
- Water; liquid:hydrocephalus.
- A prefix that means: water (as in hydroelectric) or hydrogen, (as in hydrochloride).
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