'fibril' originates from New Latin, specifically the word 'fibrilla,' which is a diminutive of 'fibra,' meaning 'fiber.'

'fibrilla' in New Latin was adopted into English as 'fibril' in the 18th century, and eventually became the modern English word 'fibril.'

Initially, it meant 'a small fiber,' and this meaning has remained consistent in modern usage, referring to fine threadlike structures in biological tissues.