- a root, as in most grasses, having numerous, very fine branches of approximately the same length.
- a root system that consists of very fine branches.
- Any of the roots in a system that is made up of many threadlike members of more or less equal length and is characteristic of monocotelydons. Fibrous roots develop from adventitious roots arising from the plant’s stem and usually do not penetrate the soil very deeply. Because their roots attach themselves firmly to soil particles, plants with fibrous root systems are especially useful in preventing soil erosion. Compare taproot.