The spine; the vertebral column.

Of or pertaining to rachitis; affected by rachitis; rickety.

Literally, inflammation of the spine, but commonly applied to the rickets. See Rickets.

A dissecting instrument for opening the spinal canal.

Of or pertaining to a race or family of men; as, the racial complexion.

In a racy manner.

The quality of being racy; peculiar and piquant flavor.

a. n. from Race, v. t. i.

To extend by the application of force; to stretch or strain; specifically, to stretch on the rack or wheel; to torture by an engine which strains the limbs and pulls the joints.

To subject to rack-rent, as a farm or tenant.

One who is subjected to paying rack-rent.

A very lean animal, esp. a horse.

A Sprengel explosive consisting of potassium chlorate and mono-nitrobenzene.

One who racks.

To make a confused noise or racket.

Any one of several species of humming birds of the genus Steganura, having two of the tail feathers very long and racket-shaped.

Having long and spatulate, or racket-shaped, tail feathers.

One who makes, or engages in, a racket.

An old wind instrument of the double bassoon kind, having ventages but not keys.

Making a tumultuous noise.

Spun yarn used in racking ropes.

An arm attached to a swinging notched arc or rack, to let off the striking mechanism of a repeating clock.

Any mechanism having a rack, as a rack and pinion.

See Rakel.

See Rakelness.

A relater; a storyteller.

The coypu.

One of a sect of Socinians or Unitarians in Poland.

See Racket.

Having a strong flavor indicating origin; of distinct characteristic taste; tasting of the soil; hence, fresh; rich.

imp. p. p. of Read, Rede.

An electronic device designed to detect objects at a distance, and determine their distance from the device, by transmitting a pulse of radio waves and measuring the time required for the echo of the pulse to return to the emitting device; as, the radar showed a plane approaching rapidly. For more information of radar, see the article What is Radar?.

imp. of Read, Rede.

To mark or paint with, or as with, raddle.

The ruddock.

A raid.

A float; a raft.

Of or pertaining to a radius or ray; consisting of, or like, radii or rays; radiated; as, (Bot.) radial projections; (Zool.) radial vessels or canals; (Anat.) the radial artery.

The bone or cartilage of the carpus which articulates with the radius and corresponds to the scaphoid bone in man.

In a radial manner.

An arc of a circle which is equal to the radius, or the angle measured by such an arc.

The quality of being radiant; brilliancy; effulgence; vivid brightness; as, the radiance of the sun.

The luminous point or object from which light emanates; also, a body radiating light brightly.

In a radiant manner; with glittering splendor.

A radiate.

An extensive artificial group of invertebrates, having all the parts arranged radially around the vertical axis of the body, and the various organs repeated symmetrically in each ray or spheromere.

One of the Radiata.

Having the principal veins radiating, or diverging, from the apex of the petiole; -- said of such leaves as those of the grapevine, most maples, and the castor-oil plant.

Emitted, or sent forth, in rays or direct lines; as, radiated heat.

In a radiate manner; with radiation or divergence from a center.

Having the marginal florets enlarged and radiating but not ligulate, as in the capitula or heads of the cornflower.

The act of radiating, or the state of being radiated; emission and diffusion of rays of light; beamy brightness.

Capable of radiating; acting by radiation.

That which radiates or emits rays, whether of light or heat; especially, that part of a heating apparatus from which the heat is radiated or diffused; as, a steam radiator.

A primitive word; a radix, root, or simple, underived, uncompounded word; an etymon. A primitive letter; a letter that belongs to the radix.

The quality or state of being radical; specifically, the doctrines or principles of radicals in politics or social reform.

Germinal principle; source; origination.

In a radical manner; at, or from, the origin or root; fundamentally; as, a scheme or system radically wrong or defective.

Quality or state of being radical.

Taking root on, or above, the ground; rooting from the stem, as the trumpet creeper and the ivy.

Rooted Having roots, or possessing a well-developed root. Having rootlike organs for attachment.

The process of taking root, or state of being rooted; as, the radication of habits.

A small branch of a root; a rootlet.

Rhizanthous.

Having the nature or appearance of a radix or root.

The rudimentary stem of a plant which supports the cotyledons in the seed, and from which the root is developed downward; the stem of the embryo; the caulicle. A rootlet; a radicel.

Of or pertaining to roots, or the root of a plant.

A radicle.

Producing numerous radicles, or rootlets.

pl. of Radius.

Of or pertaining to, or employing, or operated by, radiant energy, specifically that of electromagnetic waves with frequencies between those of infrared radiation and X-rays; hence, pertaining to, or employed in, broadcast radio or television, microwaves, radiotelephones, etc.; as, radio waves.

A group of Protozoa having both flagella and pseudopodia.

Capable of luminescence under the action of cathode rays, X rays, or any of the allied forms of radiation.

a form of instability which is a property of the atomic nuclei of certain isotopes, which causes a spontaneous change in the structure of the nucleus, accompanied by emission of energetic radiation. The radiation emitted is usually sufficient to cause ionization in matter through which it passes, and is therefore called ionizing radiation. The radiation emitted by most radioactive substances is one of three types: alpha rays, beta rays, or gamma rays. Some chemical elements have no stable isotopes, and these are referred to as radioactive elements, and the element itself is said to possess radioactivity.

A substance or device that has its conductivity altered in some way by electric waves, as a coherer.

To make a radiograph of.

Art or process of making radiographs, radiograms, or autoradiograms.

Order of rhizopods, usually having a siliceous skeleton, or shell, and sometimes radiating spicules. The pseudopodia project from the body like rays. It includes the polycystines. See Polycystina.

Of or pertaining to the Radiolaria. One of the Radiolaria.

The barbs of the radii of a feather; barbules.

A hippurite.

A forestaff.

The use of the radiometer, or the measurement of radiation.

A very sensitive modification or application of the thermopile, used for indicating minute changes of radiant heat, or temperature.

A radiotelegraphic station serving solely for determining the position of ships. The radius of operation of such stations was restricted by the International Radiotelegraphic Convention (1912) to 30 nautical miles.

An apparatus for the production of sound by the action of luminous or thermal rays. It is essentially the same as the photophone.

The art or practice of using the radiophone.

See Projector, above.

Direct observation of objects opaque to light by means of some other form of radiant energy, as x-rays.

A message transmitted by radiotelegraph.

A wireless telegraph.

Of or pertaining to radiotelegraphy; employing, or used or employed in, radiotelegraphy.

Telegraphy using the radiant energy of radio waves; wireless telegraphy; -- the term adopted for use by the Radiotelegraphic Convention of 1912.

A wireless telephone, in which the signal is conveyed by radio waves.

Treatment of disease by means of x-rays or radioactivity. Radiotherapy of cancer is based on the fact that cancer cells are more sensitive to radiation than most other cells in the body.

an earlier name for the thorium isotope thorium-228, given by its discoverer Otto Hahn. It is a radioactive substance formed as one of series of products in the chain of radioactive decay of thorium. Its immediate predecessor in the chain is Actinium-228, and it decays by alpha emission to radium-224 with a half-life of 1.91 years. The name radiothorium was given prior to the full understanding of the nature of isotopes of elements.

Consisting of rays, as light.

The pungent fleshy root of a well-known cruciferous plant (Raphanus sativus); also, the whole plant.

An intensely radioactive metallic element found (combined) in minute quantities in pitchblende, and various other uranium minerals. Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. and Mme. Curie, of Paris, who in 1902 separated compounds of it by a tedious process from pitchblende. Its compounds color flames carmine and give a characteristic spectrum. It is divalent, resembling barium chemically. The main isotope of radium found in pitchblende, radium-226, has a half-life of 1620 years, decaying first by alpha emission to radon.

A right line drawn or extending from the center of a circle to the periphery; the semidiameter of a circle or sphere.

A straight line (or the length of such line) connecting any point, as of a curve, with a fixed point, or pole, round which the straight line turns, and to which it serves to refer the successive points of a curve, in a system of polar coordinates. See Coordinate, n.

A primitive word, from which spring other words; a radical; a root; an etymon.

An intensely radioactive gaseous element produced by the radioactive decay of radium-226, which is the main isotope of radium found in pitchblende. Chemically it is an inert noble gas. Its atomic symbol is Rn. It has an atomic number of 86. The radon isotope produced by decay of radium has an atomic weight of 222.017, and this isotope decays by alpha emission with a half-life of 3.82 days. Numerous other isotopes have been observed, all radioactive and all having half-lives shorter than that of radon-222. Radon was discovered by M. and Mme. Curie, of Paris, in their studies of the radioactive substances in pitchblende. Radon was originally called radium emanation or exradio.

The chitinous ribbon bearing the teeth of mollusks; -- called also lingual ribbon, and tongue. See Odontophore.

Rasplike; as, raduliform teeth.

A promiscuous heap; a jumble; a large quantity; lumber; refuse.

Raphaelesque.

A fibrous material used for tying plants, said to come from the leaves of a palm tree of the genus Raphia.

A colorless crystalline slightly sweet substance obtained from the molasses of the sugar beet.

Resembling, or having the character of, raff, or a raff; worthless; low.

To dispose of by means of a raffle; -- often followed by off; as, to raffle off a horse.

One who raffles.

A genus of stemless, leafless plants, living parasitically upon the roots and stems of grapevines in Malaysia. The flowers have a carrionlike odor, and are very large, in one species (Rafflesia Arnoldi) having a diameter of two or three feet.

To transport on a raft, or in the form of a raft; to make into a raft; as, to raft timber.

imp. of Reave.

To make into rafters, as timber.

The business of making or managing rafts.

A man engaged in rafting.

Damp; musty.

To play or compose (a piece, melody, etc.) in syncopated time.