English Words Starting With R

• radio window

  nounC2
  /ˈreɪ.di.əʊ ˈwɪn.dəʊ/A range of radio frequencies in the electromagnetic spectrum that can pass through the Earth's atmosphere with minimal absorption, allowing for ground-based radio astronomy and satellite communication.
• radioacoustics

  nounVery Low
  /ˌreɪdiəʊəˈkuːstɪks/The branch of physics dealing with the transmission, reception, and effects of sound via radio waves.
• radioactinium

  nounVery Low (Specialist)
  /ˌreɪ.di.əʊ.ækˈtɪn.i.əm/A radioactive isotope of thorium (Th-227), part of the actinium decay series.
• radioactivate

  verbverb-transitiveC2 / Very Rare / Technical
  /ˌreɪ.di.əʊˈæk.tɪ.veɪt/To make (a substance) radioactive by bombardment with radiation or particles.
• radioactive dating

  nounC2
  /ˌreɪdiəʊˈæktɪv ˈdeɪtɪŋ/A scientific method used to determine the age of an object containing organic material by measuring the decay of radioactive isotopes.
• radioactive decay

  nounC1
  /ˌreɪdɪəʊˈæktɪv dɪˈkeɪ/The process by which an unstable atomic nucleus spontaneously loses energy by emitting radiation, transforming into a different nucleus or state.
• radioactive series

  nounSpecialized
  /ˌreɪdiəʊˈæktɪv ˈsɪəriːz/A sequence of radioactive decays from an unstable parent nuclide to a stable daughter nuclide.
• radioactive tracer

  nounC1+
  /ˌreɪ.di.əʊˈæk.tɪv ˈtreɪ.sər/A radioactive substance introduced into a biological, chemical, or physical system to follow and study its behavior, distribution, or path.
• radioactive waste

  nounC1
  /ˌreɪ.di.əʊ.æk.tɪv ˈweɪst/Unwanted, unusable radioactive material, typically generated as a byproduct of nuclear power generation, medical treatments, or military applications.
• radioactivity

  nounC1
  /ˌreɪdiəʊækˈtɪvəti/The property of certain unstable atomic nuclei to spontaneously emit energy and subatomic particles.
• radioautograph

  nounVery Low
  /ˌreɪdiəʊˈɔːtəɡrɑːf/An image produced on a photographic emulsion by radiation from a radioactive substance within the specimen, used to show the distribution of radioactive material.
• radioautography

  nounRare / Technical
  /ˌreɪdɪəʊɔːˈtɒɡrəfi/A technique for visualizing the distribution of radioactive material in a sample by exposing photographic film to it.
• radiobiology

  nounC2
  /ˌreɪdiəʊbaɪˈɒlədʒi/The branch of biology concerned with the effects of radiation on living organisms and biological systems.
• radiobroadcast

  nounverb-ambitransitiveB1
  /ˈreɪdiəʊˌbrɔːdkɑːst/The transmission of audio content via radio waves to be received by the public.
• radiocarbon

  nounC2
  /ˌreɪ.di.əʊˈkɑː.bən/A radioactive isotope of carbon, specifically carbon-14.
• radiocarbon dating

  nounC1
  /ˌreɪdiəʊˈkɑːbən ˌdeɪtɪŋ/A scientific method for determining the age of organic materials by measuring the amount of carbon-14 remaining in them.
• radiocast

  nounverb-ambitransitiveLow (Very rare/archaic term)
  /ˈreɪdiəʊkɑːst/A broadcast transmitted via radio waves.
• radiocesium

  nounVery low
  /ˌreɪ.di.əʊˈsiː.zi.əm/A radioactive isotope of the chemical element cesium, most commonly caesium-137, produced by nuclear fission and used in various applications including radiation therapy and industrial gauges.
• radiochemistry

  nounC2
  /ˌreɪ.di.əʊˈkem.ɪ.stri/The branch of chemistry concerned with radioactive substances and their chemical properties and applications.
• radiochromatography

  nounVery Low
  /ˌreɪ.di.əʊ.krəʊ.məˈtɒɡ.rə.fi/A technique that combines chromatography with the detection and quantification of radioactive substances to separate and analyze mixtures containing radioisotopes.

Showing 261–280 of 5802 words.