hydr(o)-
combining form /haɪdrəʊ/,  /haɪdrə/,  /haɪˈdrɒ/
  /haɪdrəʊ/,  /haɪdrə/,  /haɪˈdrɑː/
in nouns, adjectives and adverbs- relating to water
- hydroelectricity
 
 - (chemistry) combined with hydrogen
- hydrochloric acid
 
 
Word Originfrom Greek hudōr ‘water’.