Fibrilla

Fibrilla is a term that denotes a small fiber or filament and is used in several Romance languages as the diminutive form of fiber (for example, fibra or fibra). In English, the word is uncommon and is mostly encountered in historical texts, multilingual descriptions, or as a loanword. The origin traces to Latin fibrilla, the diminutive of fibra, meaning fiber or thread.

In scientific writing, the English equivalent is typically fibril. Fibrilla may appear in descriptive contexts to refer to tiny, threadlike structures within cells or tissues, without specifying a particular molecular composition. As a result, its usage tends to be non-specific and context-dependent, serving as a morphological label rather than a defined technical category.

Because fibrilla is not a standardized term in modern English anatomy, histology, or botany, authors who require precision usually adopt the term fibril or microfibril and specify the material or context (for example, actin fibrils, collagen fibrils, or cellulose microfibrils). When encountered in non-English texts, fibrilla often corresponds to the same concept as fibril, but the exact meaning can vary with language and discipline.

See also: fibril, microfibril, cytoskeleton, extracellular matrix, plant cell wall.