Main Entry:

fi·bril

Pronunciation:

\ˈfī-brəl, ˈfi-\

Function:

noun

Etymology:

New Latin fibrilla, diminutive of Latin fibra

Date:

1664

: a small filament or fiber: as a: root hair b (1): one of the fine threads into which a striated muscle fiber can be longitudinally split (2): neurofibril

— fi·bril·lar \ˈfi-brə-lər, ˈfī-\ adjective