microfibril A more or less crystalline aggregation of cellulose molecules, at least 60 nm long and about 200 nm² in cross-section, that is found in the cell walls of higher plants.

microfibril A microscopic fibre. Plant cell walls contain microfibrils, about 5 nm in diameter, each consisting of some 50–60 parallel cellulose chains that are associated together to form a rod or a flat ribbon. Cellulose microfibrils are arranged in layers at right angles to each other.