superfluidity Syllabification: (su·per·flu·id·i·ty)Pronunciation: /ˌso͞opərˌflo͞oˈiditē/Definition of superfluidity noun Physics the property of flowing without friction or viscosity, as in liquid helium below about 2.18 kelvins. Derivatives superfluidPronunciation: /ˈso͞opərˌflo͞o-id/ noun & adjective superfluidity in other Oxford dictionaries Definition of superfluidity in the British & World English dictionary