genu Syllabification: (ge·nu)Pronunciation: /ˈjēn(y)o͞o, ˈjen(y)o͞o/Definition of genu noun (plural genua /ˈjen(y)o͞oə/) Anatomy the knee. Anatomy & Biology a part of certain structures resembling a knee, in particular a bend in the corpus callosum of mammals. Origin: mid 19th century: from Latingenu in other Oxford dictionaries Definition of genu in the British & World English dictionary