neurofibril Syllabification: (neu·ro·fi·bril)Pronunciation: /ˌn(y)o͝orəˈfībrəl, -ˈfib-/Definition of neurofibril noun Anatomy a fibril in the cytoplasm of a nerve cell, visible by light microscopy. Derivatives neurofibrillaryPronunciation: /-ˈfibrəˌlerē/ adjective neurofibril in other Oxford dictionaries Definition of neurofibril in the British & World English dictionary