n. The root of a plant: used chiefly with reference to the roots of medicinal plants or preparations from them.n. Hence The primary source or origin; that from which anything springs, or in which it originates.n. In etymology, a. primitive word or form from which spring other words; a radical; a root.n. In mathematics, a root.n. In zoöl, and anatomy, a root; a rooted or rootlike part; a radicle: as, the radix or root of a tooth; the radix of a nerve.n. In astrology, the original figure of birth, the source of all judgments and predictions.