Root (Anatomy that part of any organ)

Collier's New Encyclopedia (1921)

in anatomy, that part of any organ or appendage ge of the body which is buried in another part. Thus the root of a nail is the portion covered by the skin; the root of a tooth, the base of it which is lodged in a socket. In astronomy, the moment from which one begins to calculate the time of revolution of a planet. In botany, the radix or descending of a plant. The roots of dicotyledons are axis exorhizal , those of monocotyledons endorhizal, and those of acotyledons heterohizal. A root has no perfect bark, true pith, medullary sheath, or true leaves, and only a thin epidermis, a few stomata, and very rarely leafbuds. Its growth is chiefly at the lower extremity. The body of a root is called the caudex, its minute sub-divisions the fibrils or radicles, and their ends the spongioles. A primary root is one formed by the downward elongation of the axis of the embryo, and is therefore in a line with the stem; secondary or lateral roots, like those of ivy, spring laterally from the stem and from the primary root. When the primary root is thicker than the branches which proceed from it, it is called a tap root, when it is no thicker than its ramifications, which conceal it from view, the root is said to be fibrous. Other forms of roots are conical, fusiform, napiform, rotund, nodose or coralline, moniliform, tuberose, or (finally) premorse. Most roots are terrestrial, a few are aërial, and a few aquatic. The chief functions of the root are to anchor the plant firmly in the ground, and to transmit upward to the stem and leaves absorbed nutriment from the soil. Roots require air, and in some cases in gardens obtain it by pushing their way into old drains. In hydraulic engineering, the end of a weir or dam where it unites with the natural bank. In mathematics, the root of a quantity is any quantity which, being taken a certain number of times as a factor, will p produce the quantity (see SQUARE ROOT). A root of a quantity may be real, or it may be imaginary. The character used to denote a root is V, called the radical sign. In music: (1) A note which, besides its own sound, gives overtones or harmonics. (2) That note from among whose overtones any chord may be selected. (3) Sometimes used by modern musicians as describing a note on which, when either expressed or implied, a chord is built up. In philology, an elementary notional syllable; that part of a word which conveys its essential meaning as distinguished from the formative parts by which this meaning is modified.