fibrilla

noun
fi·​bril·​la | \ fī-ˈbril-ə How to pronounce fibrilla (audio) , fi-; ˈfī-bri-lə How to pronounce fibrilla (audio) , ˈfib-ri-lə How to pronounce fibrilla (audio) \
plural fibrillae\ -​ˌlē How to pronounce fibrillae (audio) \

Medical Definition of fibrilla

: fibril