- fiberA single elongated piece of a given material, roughly round in cross-section, often twisted with other fibers to form thread.
- fibreA single piece of a given material, elongated and roughly round in cross-section, often twisted with other fibres to form thread.
- fibrilA fine fibre or filament.
- fibrillaSynonym of fibril (“a fine fibre or filament”).
- fibrodysplasia ossificans progressivaA very rare, disabling genetic disorder of the connective tissue in which fibrous tissue (including ligaments, muscles, and tendons) ossifies (“transforms into bone”) when damaged.