root

Root is the part of a plant that typically lies below the surface of the soil. It serves to anchor the plant, absorb water and minerals through root hairs, and store carbohydrates. Roots can form a taproot system with one main vertical root or a fibrous network of many thin roots. They often engage in symbiotic relationships with soil microbes, such as mycorrhizal fungi, which increase nutrient uptake. Specialized roots occur in some species, including pneumatophores for gas exchange in waterlogged environments and anchor roots in climbing plants. The root system is regulated by hormonal signals and is enclosed by tissues such as the endodermis, which controls the movement of solutes into the vascular system.

Mathematics: A root of an equation is a value that satisfies the equation. The nth root of a number x is a value y such that y^n = x. The most common is the square root, written as sqrt(x). Real roots are defined for nonnegative x when n is even; complex roots expand in number for nonreal values. Roots play a central role in algebra, calculus, and numerical methods.

Computing: In computing, root denotes the superuser account with unrestricted access on many Unix-like systems. It is used for system administration tasks and configuring software. The root directory, represented by / on Unix-like systems, is the top level of the file hierarchy from which all other directories descend. Access to root privileges is typically restricted and granted via mechanisms such as the sudo system.

Etymology: The word derives from Latin radix, meaning source or origin.