Definition of fibril in US English:



  • A small or slender fiber.

    ‘each muscle fiber is subdivided into smaller fibrils’
    • ‘As the number of fibrils decreases, it becomes increasingly easier to cut the next fibril because the fibrils carry larger and larger loads.’
    • ‘All fibril dimensions were therefore estimated from the height of the fibril in cross section.’
    • ‘The direction of cell growth is determined by the orientation of the cellulose fibrils in the cell wall.’
    • ‘Collagen fibrils are important for the function of musculoskeletal biomechanics in various species.’
    • ‘Many such pairs of filaments are bundled together into a structure called a fibril, and groups of fibrils make up a single muscle fiber (cell).’
    fibre, thread, strand, tendril
    View synonyms


Mid 17th century: from modern Latin fibrilla, diminutive of Latin fibra (see fiber).