2 ADJ [usu ADJ n] Radical people believe that there should be great changes in society and try to bring about these changes. □ …threats by left-wing radical groups to disrupt the proceedings. ● N‑COUNT A radical is someone who has radical views. SYNONYMS radical ADJ 1
extreme: The scheme has been condemned as extreme.
sweeping: The new government has started to make sweeping changes in the economy.
far-reaching: The economy is in danger of collapse unless far-reaching reforms are implemented.
radi|cal|ism /ræ d I kəl I zəm/ N‑UNCOUNT Radicalism is radical beliefs, ideas, or behaviour. □ Jones himself was a curious mixture of radicalism and conservatism.
radi|cal|ize /ræ d I kəla I z/ (radicalizes , radicalizing , radicalized ) in BRIT, also use radicalise VERB If something radicalizes a process, situation, or person, it makes them more radical. □ [V n] He says the opposition will radicalize its demands if these conditions aren't met. □ [V -ed] …women radicalized by feminism. □ [V -ing] The trial was a radicalizing experience for her. ● radi|cali|za|tion /ræ d I kəla I ze I ʃ ə n/ N‑UNCOUNT □ [+ of ] …the radicalization of the conservative right.
ra|dic|chio /ræd I kioʊ, [AM ] rɑːdiː -/ N‑UNCOUNT Radicchio is a vegetable with purple and white leaves that is usually eaten raw in salads.
ra|dii /re I dia I / Radii is the plural of radius .
ra|dio ◆◆◆ /re I dioʊ/ (radios , radioing , radioed )
1 N‑UNCOUNT [oft N n] Radio is the broadcasting of programmes for the public to listen to, by sending out signals from a transmitter. □ The announcement was broadcast on radio and television.
2 N‑SING You can refer to the programmes broadcast by radio stations as the radio . □ A lot of people tend to listen to the radio in the mornings.
3 N‑COUNT A radio is the piece of equipment that you use in order to listen to radio programmes. □ He sat down in the armchair and turned on the radio.
4 N‑UNCOUNT [oft N n] Radio is a system of sending sound over a distance by transmitting electrical signals. □ They are in twice daily radio contact with the rebel leader.
5 N‑COUNT A radio is a piece of equipment that is used for sending and receiving messages. □ …the young constable who managed to raise the alarm on his radio.
6 VERB If you radio someone, you send a message to them by radio. □ [V adv/prep] The officer radioed for advice. □ [V that] A few minutes after take-off, the pilot radioed that a fire had broken out. [Also V n, V ]
radio|ac|tive /re I dioʊæ kt I v/ ADJ Something that is radioactive contains a substance that produces energy in the form of powerful and harmful rays. □ The government has been storing radioactive waste at Fernald for 50 years. ● radio|ac|tiv|ity /re I dioʊækt I v I ti/ N‑UNCOUNT □ …waste which is contaminated with low levels of radioactivity.
ra |dio as|tro no|my N‑UNCOUNT Radio astronomy is a branch of science in which radio telescopes are used to receive and analyse radio waves from space.
radio|car|bon /re I dioʊkɑː r bən/ also radio carbon N‑UNCOUNT [usu N n] Radiocarbon is a type of carbon which is radioactive, and which therefore breaks up slowly at a regular rate. Its presence in an object can be measured in order to find out how old the object is. □ The most frequently used method is radiocarbon dating.
ra dio-contro lled ADJ [usu ADJ n] A radio-controlled device works by receiving radio signals which operate it. □ …radio-controlled model planes.
ra|di|og|ra|pher /re I diɒ grəfə r / (radiographers ) N‑COUNT A radiographer is a person who is trained to take X-rays.
ra|di|og|ra|phy /re I diɒ grəfi/ N‑UNCOUNT Radiography is the process of taking X-rays.
radio|logi|cal /re I diəlɒ dʒ I k ə l/
1 ADJ [ADJ n] Radiological means relating to radiology. □ …patients subjected to extensive radiological examinations.
2 ADJ [ADJ n] Radiological means relating to radioactive materials. □ …the National Radiological Protection Board's guidelines for storing nuclear waste.
ra|di|olo|gist /re I diɒ lədʒ I st/ (radiologists ) N‑COUNT A radiologist is a doctor who is trained in radiology.
ra|di|ol|ogy /re I diɒ lədʒi/ N‑UNCOUNT Radiology is the branch of medical science that uses X-rays and radioactive substances to treat diseases.
ra |dio te le|phone (radio telephones ) N‑COUNT A radio telephone is a telephone which carries sound by sending radio signals rather than by using wires. Radio telephones are often used in cars.
ra |dio te le|scope (radio telescopes ) N‑COUNT A radio telescope is an instrument that receives radio waves from space and finds the position of stars and other objects in space.
radio|thera|pist /re I dioʊθe rəp I st/ (radiotherapists ) N‑COUNT A radiotherapist is a person who treats diseases such as cancer by using radiation.
radio|thera|py /re I dioʊθe rəpi/ N‑UNCOUNT Radiotherapy is the treatment of diseases such as cancer by using radiation.
rad|ish /ræ d I ʃ/ (radishes ) N‑VAR Radishes are small red or white vegetables that are the roots of a plant. They are eaten raw in salads.
ra|dium /re I diəm/ N‑UNCOUNT Radium is a radioactive element which is used in the treatment of cancer.
ra|dius /re I diəs/ (radii /re I dia I /)
1 N‑SING The radius around a particular point is the distance from it in any direction. □ Nigel has searched for work in a ten-mile radius around his home.