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RAD'DOCK, or RUD'DOCK, n. [from red, ruddy, – which see.]

A bird, the red-breast of Europe. – Shak.

RA'DI-AL, a. [from L. radius, a ray, a rod, a spoke. See Radius and Ray.]

Pertaining to the radius, one of the bones of the fore arm of the human body; as, the radial artery or nerve. – Rush. The radial muscles are two muscles of the fore arm, one of which bends the wrist, the other extends it. – Encyc. Parr. Radial curves, in geometry, curves of the spiral kind, whose ordinates all terminate in the center of the including circle, and appear like so many semidiameters. – Bailey.

RA'DI-ANCE, or RADI-AN-CY, n. [L. radians, radio, to beam or shoot rays. See Radius and Ray.]

Properly, brightness shooting in rays or beams; hence in general, brilliant or sparkling luster; vivid brightness; as, the radiance of the sun. The Son / Girt with omnipotence, with radiance crown'd / Of majesty divine. – Milton.


Shooting or darting rays of light; beaming with brightness; emitting a vivid light or splendor; as, the radiant sun. Mark what radiant state she spreads. – Milton. Radiant in glittering arms and beamy pride. – Milton.


In optics the luminous point or object from which light emanates, that falls on a mirror or lens.

RA'DI-ANT-LY, adv.

With beaming brightness; with glittering splendor.

RA'DI-A-RY, n.

The same as Radiata. – Kirby.

RA-DI-A'TA, n.

The fourth great division of the animal kingdom, including those animals whose parts are arranged round an axis, and on one or several radia, or on one or several radii, or on one or several lines extending from one pole to the other. This division comprehends the echinodermata, the entozoa, the acalepha, the polypi or polypodes, and the infusoria. – Cuvier.


In botany, a rayed or radiate flower, is compound flower consisting of a disk, in which the corollets or florets are tubular, and of a ray, in which the floret are ligulate or strap-shaped. – Martyn. Or a flower with several semiflosculous florets set round a disk in form of a radiant star. – Encyc.

RA'DI-ATE, v.i. [L. radio. See Ray.]

  1. To issue in rays, as light; to dart, as beams of brightness; to shine. Light radiates from luminous bodies directly to our eyes. – Locke.
  2. To issue and proceed in direct lines from a point.

RA'DI-ATE, v.t.

To enlighten; to illuminate; to shed light or brightness on. [Usually irradiate.] Hewyt.

RA'DI-A-TED, pp.

  1. Adorned with rays of light. – Addison.
  2. Having crystals diverging from a center. – Mineralogy.

RA'DI-A-TING, ppr.

Darting rays of light; enlightening; as, the radiating point in optics.

RA-DI-A'TION, n. [L. radiatio.]

  1. The emission and diffusion of rays of light; beamy brightness. – Bacon.
  2. The shooting of any thing from a center, like the diverging rays of light.

RAD'IC-AL, a. [Fr. from L. radicalis, from radix, root. See Race and Ray.]

  1. Pertaining to the root or origin; original; fundamental; as, a radical truth or error; a radical evil; a radical difference of opinions or systems.
  2. Implanted by nature; native; constitutional; as, the radical moisture of a body. – Bacon.
  3. Primitive; original; underived; uncompounded; as, a radical word.
  4. Serving to origination.
  5. In botany, proceeding immediately from the root; as, a radical leaf or peduncle. – Martyn.


  1. In philology, a primitive word; a radix, root, or simple underived uncompounded word.
  2. A primitive letter; a letter that belongs to the radix.
  3. In modern politics, a person who advocates a radical reform, or extreme measures in reformation.
  4. In chimistry, an element, or a simple constituent part of a substance, which is incapable of decomposition. – Parke. That which constitutes the distinguishing part of an acid or a base, by its union with oxygen, or other acidifying and basifying principles. – Ure. Compound radical, is a base composed of two or more substances. Thus a vegetable acid having a radical composed of hydrogen and carbon, is said to be an acid with a compound radical. Radical quantities, in algebra, quantities whose roots may be accurately expressed in numbers. The term is sometimes extended to all quantities under the radical sign. Radical sign, the sign √ placed before any quantity, denoting that its root is to be extracted; thus, √a or √(a+b). – Encyc. Bailey.


The doctrine or principle of making radical reform in government, by overturning and changing the present state of things.


  1. Origination. – Brown.
  2. A being radical; a quantity which has relation to a root.

RAD'IC-AL-LY, adv.

  1. Originally; at the or root; fundamentally; as, a scheme or system radically wrong or defective.
  2. Primitively; essentially; originally; without derivation. These great orbs thus radically bright. – Prior.


The state of being radical or fundamental.

RAD'IC-ANT, a. [L. radicans.]

In botany, rooting; as, a radicant stem or leaf. – Lee. Martyn.

RAD'I-CANT, or RAD'I-CA-TING, ppr. [or adj.]

In botany, taking root from some part above ground, as the joint of a stem, the extremity of a leaf, &c.

RAD'IC-ATE, or RAD'IC-A-TED, pp. [or a.]

Deeply planted. Prejudices of a whole race of people radicated by a successions of ages. – Burke.

RAD'IC-ATE, v.t. [L. radicatus, radicor, from radix, root.]

To root; to plant deeply and firmly; as, radicated opinions; radicated knowledge. – Glanville. Meditation will radicate these seeds. – Hammond.

RAD-IC-A'TION, a. [from radicate.]

  1. The process of taking root deeply; as, the radication of habits.
  2. In botany, the disposition of the root of a plant with respect to the ascending and descending candex. – Lee.