radioactive fallout(RAY-dee-oh-AK-tiv...) Airborne radioactive particles that fall to the ground during and after an atomic bombing, nuclear weapons test, or nuclear plant…
radioactive iodine(RAY-dee-oh-AK-tiv I-oh-dine) A radioactive form of iodine, often used for imaging tests or to treat an overactive thyroid, thyroid cancer, and certain…
radioactive palladium(RAY-dee-oh-AK-tiv puh-LAY-dee-um) A radioactive form of palladium (a metallic element that resembles platinum).
radioactive seed(RAY-dee-oh-AK-tiv...) A small, radioactive pellet that is placed in or near a tumor.
Radioactive WasteMaterials left over from making nuclear energy. Radioactive waste can living organisms if it is not stored safely.
RadioactivityThe spontaneous decay of disintegration of an unstable atomic nucleus accompanied by the emission of radiation.
radiobeacon stationA station in the radionavigation service the emissions of which are intended to enable a mobile station to determine its bearing or direction in relation…
radiocarbon (<sup>14</sup>C)a radioactive isotope of carbon. Since it decays with a half-life of 5570 years, its concentration in organic materials relative to the stable…
radiocarbon datingthe process of providing an absolute age for a material by using measurements of the amount of radiocarbon it still contains.
radiocommunicationTelecommunication by means of radio waves. [NTIA] [RR] [47CFR]
radiocommunication serviceA service as defined in this Section [of the Radio Regulations] involving the transmission, emission and/or reception of radio waves for specific…
radiodeterminationThe determination of the position, velocity and/or other characteristics of an object, or the obtaining of information relating to these parameters, by…
radiodetermination-satellite serviceA radiocommunication service for the purpose of radiodetermination involving the use of one or more space stations.
RadiofacsimileAlso known as HF FAX, radiofax or weatherfax, is a means of broadcasting graphic weather maps and other graphic images via HF radio.
radiofrequency ablation(RAY-dee-oh-FREE-kwen-see uh-BLAY-shun) A procedure that uses radio waves to heat and destroy abnormal cells.
radioimaging(RAY-dee-oh-IH-muh-jing) A method that uses radioactive substances to make pictures of areas inside the body.
Radioimmunoassay(Abbreviation: RIA). An assay based on the use of a radioactively labelled antibody, where the amount of radiation detected indicates the amount of target…
radioimmunodiagnostics(RAY-dee-oh-IH-myoo-noh-DY-ug-NOS-tix) The use of radiolabeled monoclonal antibodies to help diagnose diseases, including cancer.
radioimmunoguided surgery(RAY-dee-oh-IH-myoo-noh-GIDE-ed SER-juh-ree) A procedure that uses radioactive substances to locate tumors so that they can be removed by surgery.
radioimmunotherapeutics(RAY-dee-oh-IH-myoo-noh-THAYR-uh-PYOO-tix) The use of radiolabeled monoclonal antibodies to treat diseases, including cancer.
radioimmunotherapy(RAY-dee-oh-IH-myoo-noh-THAYR-uh-pee) A type of systemic radiation therapy in which a radioactive substance is linked to an antibody that locates and…
radioisotope(RAY-dee-oh-I-suh-tope) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
Radioisotope Snow GageA snow water equivalent gage based on the absorption of gamma radiation by snow; this gage can measure up to 55 inches water equivalent with a 2 to 5…
radiolabeled(RAY-dee-oh-LAY-buld) Any compound that has been joined with a radioactive substance.
radiolocationRadiodetermination used for purposes other than those of radionavigation. [NTIA] [RR] [47CFR]
radiolocation land stationA station in the radiolocation service not intended to be used while in motion. [NTIA] [RR] [47CFR]
radiolocation mobile stationA station in the radiolocation service intended to be used while in motion or during halts at unspecified points. [NTIA] [RR] 2.
radiolocation serviceA radiodetermination service for the purpose of radiolocation. [NTIA] [RR]
radiologic exam(RAY-dee-uh-LAH-jik ig-ZAM) A test that uses radiation or other imaging procedures to find signs of cancer or other abnormalities.
Radiologist(RAY-dee-AH-loh-jist) A doctor who specializes in creating and interpreting pictures of areas inside the body.
radiology(RAY-dee-AH-loh-jee) The use of radiation (such as x-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose…
radiometryThe science of radiation measurement. See Table of Radiometric Terms. TABLE OF RADIOMETRIC TERMS Term Symbol Quantity Unit radiant energy Q energy joule…
radionavigationRadiolocation intended for the determination of position or direction or for obstruction warning in navigation. [JP 1-02] 2.
radionavigation land stationA station in the radionavigation service not intended to be used while in motion. [NTIA] [RR]
radionavigation mobile stationA station in the radionavigation service intended to be used while in motion or during halts at unspecified points. [NTIA] [RR]
radionavigation-satellite serviceA radiodetermination-satellite service used for the purpose of radionavigation. This service may also include feeder links necessary for its operation.
Radionuclide(RAY-dee-oh-NOO-klide) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
radionuclide scanning(RAY-dee-oh-NOO-klide SKAN-ing) A procedure that produces pictures (scans) of structures inside the body, including areas where there are cancer cells.
radiopharmaceutical(RAY-dee-oh-FAR-muh-SOO-tih-kul) A drug containing a radioactive substance that is used in the diagnosis and treatment of cancer and in pain management of…
radiosensitization(RAY-dee-oh-SEN-sih-tih-ZAY-shun) The use of a drug that makes tumor cells more sensitive to radiation therapy.
radiosensitizer(RAY-dee-oh-SEN-sih-TIZE-er) A drug that makes tumor cells more sensitive to radiation therapy.
RadiosondeAn instrument that is carried aloft by a balloon to send back information on atmospheric temperature, pressure and humidity by means of a small…
radiosurgery(RAY-dee-oh-SER-juh-ree) A type of external radiation therapy that uses special equipment to position the patient and precisely give a single large dose…
radiotelegramA telegram, originating in or intended for a mobile station or a mobile Earth station transmitted on all or part of its route over the radiocommunication…
radiotelemetryTelemetry by means of radio waves. [NTIA] [RR]
radiotelephone callA telephone call, originating in or intended for a mobile station or a mobile Earth station, transmitted on all or part of its route over the…
radiotelephone distress frequencyAn international distress and calling frequency for mobile radiotelephone stations, survival craft, and emergency position-indicating radio beacons.
radiotelex callA telex call, originating in or intended for a mobile station or a mobile Earth station, transmitted on all or part of its route over the…
Radiotherapeutic ablation(ray"-dee-o-ther"-uh-pyoo'-tik ay-blay"-shun) therapy using ionizing radiation to remove or destroy a part.
radiotherapy(RAY-dee-oh-THAYR-uh-pee) The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink…
RADIUSHorizontal distance from the center of rotation.
Radius of Maximum WindsThe distance from the center of a tropical cyclone to the location of the cyclone's maximum winds.
RadonA toxic gas found in the soil beneath a house that can contribute to cancer and other illnesses.
RafterA construction element used for ceiling support.
Raftilose Synergy 1(RAF-tih-lose SIH-ner-jee ...) A substance that is used to improve the health of the digestive system and bones and is being studied in the prevention of…
RaggedA flop (or board) that doesn't appear to help anybody very much. A flop that came down J ♦-6♥-2 ♣ would look ragged.
RAIDA raid is a large-scale attack on an area by a group of players.
RAID (Redundant Array of Independent Disk)Redundant Array of Inexpensive Disks. A technology in which data is stored in distributed fashion across multiple disk drives to achieve redundancy and…
RAID (Redundant Array of Independent Disks)A method of accessing multiple individual disks as if the array were one larger disk, spreading data access out over these multiple disks.
RAID (Redundant Arrays of Independent Disks)A way of storing the same data in different places on multiple hard disks. Storing data on multiple disks can improve performance by balancing input and…
RAID 0 (striped disks without parity)Block striping across multiple drives is provided, yielding higher performance than is possible with individual drives.
RAID 1 (mirrored disks without parity)Provides data protection by duplicating all data from a primary drive on a secondary drive. Drives are paired and mirrored.
RAID disk scrubbingThe process by which the system reads each disk in the RAID group and tries to fix media errors by rewriting the data to another disk area.
RAID groupA set of data disks and a parity disk that implement RAID 4.
RAID Level MigrationA process to change the RAID level of an existing RAID array without taking the server offline. Also known as Morphing.
RAID LevelsRAID levels refer to different array architectures that offer various advantages in terms of data availability, cost, and performance.
RAID Management SoftwareSoftware that makes installation, configuration, and management of RAID arrays easy.
RainPrecipitation that falls to earth in drops more than 0.5 mm in diameter.
Rain FootSlang for a horizontal bulging near the surface in a precipitation shaft, forming a foot-shaped prominence. It is a visual indication of a wet microburst.
Rain ForestA forest which grows in a region of heavy annual precipitation. There are two major types, tropical and temperate.
rain gageA device, usually a cylindrical container, for measuring rainfall.
Rain GaugeAn instrument for measuring the quantity of rain that has fallen.
Rain Induced FogWhen warm rain falls through cooler air, water evaporates from the warm rain. It subsequently condenses in the cool air forming fog.
Rain ShadowAn area of reduced precipitation on the lee side of a mountain barrier caused by warming of air and dissipation of cloudiness as air descends the barrier.
Rain shadow effectThe region on the lee (sheltered) side of a mountain or mountain range where the precipitation is noticeably less than on the windward side, because the…
Rain ShieldIn a hurricane, a solid or nearly solid area of rain that typically becomes heavier as one approaches the eye.
Rain-free BaseA dark, horizontal cloud base with no visible precipitation beneath it. It typically marks the location of the thunderstorm updraft.
RainbowA flop that contains three different suits, thus no flush can be made on the turn.
Rainbow Series[A] set of publications that interpret Orange Book requirements for trusted systems. [INFOSEC-99]
rainbow trout, rainbowsA member of the salmon/trout family. Rainbows are not native to Arizona.
RainfallThe amount of precipitation of any type, primarily liquid. It is usually the amount that is measured by a rain gauge.
Rainfall EstimatesA series of NEXRAD products that employ a Z-R relationship to produce accumulations of surface rainfall from observed reflectivity.