| a combining form meaning “water,” used in the formation of compound words: hydroplane; hydrogen. |
| a combining form representing hydrogen in compound words, denoting esp. a combination of hydrogen with some negative element or radical: hydrobromic. |
| hydro- or hydr- pref.
[Greek hudro-, hudr-, from hudōr; see wed-1 in Indo-European roots.] |
hydro- or hydr-
pref.
Water; liquid: hydrocephalus.
Hydrogen: hydrochloride.