hydrant Syllabification: (hy·drant)Pronunciation: /ˈhīdrənt/Translate hydrant | into French | into German | into Italian | into Spanish Definition of hydrant noun an upright water pipe, especially one in a street, with a nozzle to which a fire hose can be attached. Origin: early 19th century (originally US): formed irregularly from hydro- 'relating to water' + -anthydrant in other Oxford dictionaries Definition of hydrant in the British & World English dictionary