absolute age noun (geology) see radiometric under radio-

absolute alcohol noun

Water-free alcohol

absolute ceiling noun

The altitude above sea level, in standard atmospheric conditions, at which the rate of ascent of an aircraft would be zero (cf service ceiling under service¹)

absolute humidity noun

Humidity expressed as grams of water per cubic metre of air

absolute magnitude noun

The magnitude that a star would have at a standard distance of 10 parsecs

absolute majority noun

A vote gained by a candidate which is greater than the total number of votes for all other candidates

absolute monopoly noun (economics)

A situation in which a single organization has total control over the output of a product, commodity or service for which there is no substitute

absolute music noun

Music which does not attempt to illustrate or describe (cf programme music)

absolute pitch noun

1. The pitch of a note as determined by the number of vibrations per second, perfect pitch
2. A sense of or memory for absolute pitch

absolute privilege noun (law)

A privilege that protects speakers in a parliament, law court, etc in making (even malicious) statements from the floor, from possible charges under the laws of slander

absolute temperature noun

Temperature measured on the Kelvin scale or Rankine scale

absolute undertaking noun (commerce)

A promise by a party to a contract that he or she shall take absolute responsibility for something which is necessary for the performance of the contract, eg obtaining a licence to sell the goods

absolute units plural noun

Those derived directly from fundamental units and not based on arbitrary numerical definitions

absolute value noun

The magnitude of a numerical value, irrespective of its relation to other values

absolute zero noun

The zero of the absolute scale of temperature (−273.15ºC), the lowest temperature theoretically possible, at which entropy is zero

radio- /rā-di-ō-/

combining form

1. (some of the following words may also be hyphenated) denoting: rays
2. Radiation
3. Radium
4. Radius
5. Radio, wireless
6. (of product or isotope) radioactive, as in rādio-actinˈium and rādio-thoˈrium, both isotopes of thorium, or rādioelˈement (chem)

rādioactˈive adjective

Emitting radiation (radioactive waste any radioactive waste material, esp spent fuel from a nuclear reactor)

rādioactˈively adverb

rādioactivˈity noun

1. Spontaneous disintegration, first observed in certain naturally occurring heavy elements (radium, actinium, uranium, thorium) with emission of α-rays, β-rays, and γ-rays
2. The subatomic particles or radiation emitted by this process
3. Disintegration brought about by high-energy bombardment

rādioautˈograph noun

Another term for autoradiograph

rādiobiolˈogist noun

rādiobiolˈogy noun

The study of the effects of radiation on living tissue

rādiocarˈbon noun

A radioactive isotope of carbon, specif carbon-14 (rādiocarbon dating a method of establishing the age of any organic material, eg wood or paper, by measuring the content of carbon-14)

rādiochemˈical adjective

rādiochemˈist noun

rādiochemˈistry noun

The chemistry of radioactive elements and compounds

rādioelˈement noun

A radioisotope

rādiogenic /-jenˈik/ adjective

1. Produced by radioactive disintegration
2. Suitable for broadcasting

rādiogoniomˈeter noun

A radio direction-finder

rāˈdiogram noun

1. An X-ray photograph, a radiograph
2. A wireless telegram
3. (for rādio-gramˈophone) a combined wireless receiver and gramophone

rāˈdiograph /-gräf/ noun

1. A recorded image, usu a photograph, produced by X-rays
2. Formerly, the wireless telegraph

rādiogˈrapher noun

A technician involved in radiology, eg in the taking of radiographs or in radiotherapy

rādiographic /-grafˈik/ adjective

rādiographˈically adverb

rādiography /-ogˈrə-fi/ noun

1. Photography of the interior of a body or specimen by radiations other than light, such as X-rays, etc
2. Formerly, radiotelegraphy
3. The study of radioactivity

rāˈdioimmunoassˈay (or /-as-āˈ/) noun

An immunoassay of a substance which has been labelled (qv) with a radioactive substance

rādioīˈsotope noun

A radioactive isotope of a stable element

rādioīsotopˈic adjective

rādiolaˈbelled adjective

Labelled (qv) with a radioactive substance

rādiolocāˈtion noun

1. Position-finding by radio signals
2. Radar

rādiologˈic or rādiologˈical adjective

rādiologˈically adverb

rādiolˈogist noun

A doctor specializing in the use of X-rays and in methods of imaging the internal structure of the body for diagnosis and treatment of disease (now often called a radiation oncologist)

rādiolˈogy noun

The study of radioactivity and radiation or their application to medicine, eg as X-rays, or as treatment for certain diseases

rādioluˈcent adjective

Transparent to electromagnetic radiation

rādioluminescˈence noun

Luminous radiation arising from radiation from a radioactive material

rādiolˈysis noun

Chemical decomposition induced by ionizing radiation

rādiolytˈic adjective

rādiometeorˈograph noun same as radiosonde below

rādiomˈeter noun

Any instrument that measures radiant energy

rādiometˈric adjective

(radiometric age the radiometrically determined age of a fossil, mineral, rock, event, etc, usu given in years (also absolute age); radiometric dating the method of obtaining a geological age by measuring the relative abundance of radioactive parent and daughter isotopes in geological materials)

rādiometˈrically adverb

rādiomˈetry noun

rādiomimetˈic adjective

(of drugs) imitating the physiological action of X-rays

rādionˈics singular noun

Diagnosis and treatment at a distance on radiesthetic principles, using a device that tunes in to radiations from samples of hair, nail clippings, etc

rādionūˈclide noun

Any radioactive atom of an element identified by the number of neutrons and protons in its nucleus, and its energy state (radionuclide imaging (radiology) the use of radionuclides to image the physiology or anatomy of the body)

rāˈdiopager noun

A radio receiver which functions as a pager

rāˈdiopaging noun

rādiopaque /-pākˈ/ adjective

Opaque to radiation (esp X-rays)

rāˈdiophōne noun

1. An instrument for producing sound by radiant energy
2. A radiotelephone

rādiophonic /-fonˈik/ adjective

1. (of music) produced electronically
2. Producing electronic music

rādiophonˈics singular noun

rādiophonist /-ofˈə-nist/ noun

rādiophˈony noun

rādioresistˈant adjective

Able to withstand considerable radiation doses without injury

rāˈdioscope noun

A machine used in rādiosˈcopy, examination by X-rays, etc

rādioscopic /-skopˈik/ adjective

rādioscopˈically adverb

rādiosenˈsitive adjective

Quickly injured or changed by radiation

rādiosenˈsitize or rādiosenˈsitise transitive verb

To make (eg cancer cells) more radiosensitive

rāˈdiosonde noun

(Fr sonde plummet, probe) an apparatus for ascertaining atmospheric conditions at great heights, consisting of a hydrogen-filled balloon, radio transmitter(s), etc (also rādiometeorˈograph)

rādio-stronˈtium noun

A radioactive isotope of strontium, esp strontium-90

rādiotelˈegram noun

rādiotelˈegraph noun

rādiotelegˈraphy noun

rādiotelemˈeter noun see under telemeter

rādiotelˈephone noun

A device which receives and transmits by means of radio waves (rather than wires) and which functions as a telephone (eg in cars and other vehicles)

rādiotelephˈony noun

rādiotelˈetype noun

A teleprinter that receives and transmits by radio

rādiother'apy or rādiotherapeutˈics noun

Treatment of disease, esp cancer, by radiation, eg by X-rays, etc

rādiotherˈapist noun

rādiotoxˈic adjective

Of or relating to the toxic effects of radiation or radioactive material