English Words Starting With R

• ratio test

  nounC1
  /ˈreɪ.ʃi.əʊ ˌtest/A specific mathematical test used to determine the convergence or divergence of an infinite series by examining the limit of the ratio of successive terms.
• ratiocinate

  verbverb-intransitiveC2 (Very Low Frequency)
  /ˌræt.iˈɒs.ɪ.neɪt/To think or argue logically and methodically; to reason systematically.
• ratiocination

  nounC2 (Very Low Frequency)
  /ˌrætɪˌɒsɪˈneɪʃn/The process of exact, logical thinking and reasoning.
• ratiometer

  nounTechnical / Extremely Rare
  /ˌreɪʃiˈɒmɪtə(r)/An instrument for measuring a ratio between two quantities.
• ration

  nounverbverb-transitiveC1
  /ˈraʃ(ə)n/A fixed, often limited, amount of food, fuel, or another commodity allowed to each person or group, especially during times of shortage.
• rational

  adjectivenounC1
  /ˈræʃ(ə)n(ə)l/Based on or using reason, logic, or clear thinking rather than emotions or beliefs.
• rational form

  nounLow (C1/C2)
  /ˈræʃ.nəl ˈfɔːm/In mathematics, an algebraic expression rewritten as a ratio of two polynomials, with no roots (or radicals) in the denominator and no fractions within the numerator or denominator.
• rational function

  nounSpecialized / Academic
  /ˌræʃ.ən.əl ˈfʌŋk.ʃən/A function that can be expressed as the ratio of two polynomials.
• rational number

  nounC1
  /ˌræʃ.ən.əl ˈnʌm.bər/A number that can be expressed as a fraction p/q, where p and q are integers and q is not zero.
• rational operation

  nounLow
  /ˌræʃ.ən.əl ˌɒp.ərˈeɪ.ʃən/A fundamental arithmetic calculation (addition, subtraction, multiplication, division) performed on rational numbers.
• rational-emotive therapy

  nounC2
  /ˌræʃ.ən.əl ɪˈməʊ.tɪv ˈθer.ə.pi/A form of psychotherapy that focuses on changing irrational beliefs that lead to emotional distress and maladaptive behaviour, developed by Albert Ellis.
• rationale

  nounC1
  /ˌræʃ.əˈnɑːl/The fundamental reasons or logical basis for a course of action, belief, or system.
• rationalism

  nounC1
  /ˈræʃ(ə)nəlɪz(ə)m/The philosophical belief that reason and logical analysis are the primary sources of knowledge and truth, superior to sensory experience or religious doctrine.
• rationality

  nounC1
  /ˌræʃ.ənˈæl.ə.ti/The quality or state of being based on reason, logic, and clear thinking, rather than on emotions or beliefs.
• rationalization

  nounC1
  /ˌræʃ.ən.əl.aɪˈzeɪ.ʃən/The process of making something more efficient, logical, or justifiable, often by reorganizing or explaining it in a systematic way.
• rationalize

  verbverb-intransitiveverb-transitiveC1
  /ˈræʃ.nə.laɪz/To attempt to explain or justify (one's own or another's behavior or attitude) with logical, plausible reasons, even if these are not the true motives.
• rations

  plural-nounB2
  /ˈraʃ(ə)nz/A fixed allowance or portion of food or provisions, especially for military personnel or in times of scarcity.
• ratisbon

  nounVery Low
  /ˈrætɪsbən/An archaic English name for the German city of Regensburg.
• ratite

  adjectivenounC2
  /ˈrætaɪt/A flightless bird with a flat breastbone lacking a keel for muscle attachment.
• ratline

  nounC1/C2
  /ˈrætlɪn/Any of the small lines or ropes forming the rungs of a rope ladder on a ship, used for climbing the rigging.

Showing 941–960 of 5802 words.