pennywort Syllabification: (pen·ny·wort)Pronunciation: /ˈpenēwərt, -ˌwôrt/Definition of pennywort noun any of a number of plants with rounded leaves, in particular. a creeping perennial of the genus Hydrocotyle, family Umbelliferae: numerous species, including the North American water pennywort (H. americana). pennywort in other Oxford dictionaries Definition of pennywort in the British & World English dictionary