Radical

(rad'e-kal.) (Bot.) Belonging to, or springing directly from, the root of a plant:-a term used adjective ly. (Gram.) Referring to the root or origin of aw ord. (Chem.) An element or constituent part of a substance. R. are either simple or compound.(Gram.) A primitive word, as distinguished from compounds and derivatives.-(pl.) (Eng. Pol.) A title given to that political party which advocates advanced reforms of a democratic or ultra-liberal character.-R. Quantities. (Algeb.) Those quantities whose roots may be accurately expre ed in numbers. -R. Sign, V, the symbol which denotes that a root is to be extracted: it is y, a modification of the letC ter R. Thus ya, means the square root of a: yd, the cube root ofd; 16, the eighth root of16. ル Radicel, (rad'e-sel.) [From L. rad iz, a root.) (Bot.) A little root. Radicle, (rad'e-kl,) or RADICULE. [Same der iv.] (Bot.) The first root of a plant, rudimentary in the embryo. Radish, (rad'ish.) (Bot.) See RAPHANUS. Radius, (ra'de-us,) Eng. pl. RADIUSES; L. RADII. [ L., a ray. ] (Bot.) The circumference or outer side of the circle formed by umbels or capitules or of other such parts. (Trigon.) The sine of 90degrees. (Anat.) The outer bone of the fore-arm, descending along with the ulna from the elbow to the wrist;-so called from its supposed resemblance to the spoke of a wheel. -(Geom.) A right line extending from the centre of a circle to the periphery; and hence the semi-diameter of the circle.- Radius Vector. (Ast.) A straight line draw: from the centre of force to the position of a body which describes its orbit round that centre; if the orbit is a circle, the radius-vector is invariable in its length,but constantly changes if the orbit be any of the other conic sections. [s. 750]