English Words Starting With O

• operant

  adjectivenounC1/C2 (Low-frequency, specialized)
  /ˈɒpərənt/Functioning or producing effects; an entity that operates or acts, particularly in psychology where behavior produces consequences.
• operant conditioning

  nounC1
  /ˈɒp.ər.ənt kənˈdɪʃ.ən.ɪŋ/A learning process in which the strength of a behavior is modified by its consequences (reinforcement or punishment).
• operant learning

  nounC1/C2
  /ˈɒp.ər.ənt ˈlɜː.nɪŋ/A theory of learning in which behavior is shaped and maintained by its consequences (rewards or punishments).
• operate

  verbverb-intransitiveverb-transitiveB2
  /ˈɒp.ər.eɪt/To function or work; to control the functioning of a machine, system, or organization.
• operatic

  adjectivenounC1
  /ˌɒp.ərˈæt.ɪk/Of, relating to, or characteristic of opera, a dramatic art form combining singing and orchestral music.
• operating budget

  nounC1
  /ˈɒpəreɪtɪŋ ˈbʌdʒɪt/A financial plan detailing the expected revenues and expenses for the day-to-day running of an organisation, department, or project over a specific period.
• operating income

  nounC1
  /ˌɒp.ər.eɪ.tɪŋ ˈɪŋ.kʌm/The profit generated from a company's core business operations after subtracting operating expenses.
• operating room

  nounB2
  /ˈɒpəreɪtɪŋ ruːm/A specially equipped room in a hospital or clinic where surgical operations are performed.
• operating system

  nounB2
  /ˈɒpəreɪtɪŋ ˌsɪstəm/The main software that manages all hardware and other software on a computer, smartphone, or other device.
• operating table

  nounB2
  /ˈɒpəreɪtɪŋ ˌteɪbl̩/A special table in a hospital operating theatre on which a patient lies during a surgical operation.
• operating theatre

  nounB2
  /ˈɒpəreɪtɪŋ ˌθɪətə/A specially equipped room in a hospital where surgical operations are performed.
• operation

  nounB1
  /ˌɒp.ərˈeɪ.ʃən/The process of functioning or working; a planned activity involving many people and steps.
• operation barbarossa

  nounC1
  /ˌɒp.ərˈeɪ.ʃən ˌbɑː.bəˈrɒs.ə/The codename for Nazi Germany's invasion of the Soviet Union during World War II, which began on 22 June 1941.
• operation desert storm

  nounLow
  /ˌɒp.ərˈeɪ.ʃən ˈdez.ət stɔːm/The official US military codename for the combat phase of the 1991 Gulf War, a major multinational military campaign to liberate Kuwait from Iraqi occupation.
• operation overlord

  nounLow (specific historical term). Very rare in everyday conversation.
  /ˌɒp.ərˈeɪ.ʃən ˈəʊ.və.lɔːd/The codename for the Allied invasion of Normandy (D-Day) during World War II, launched on 6 June 1944.
• operation sealion

  nounC1
  /ˌɒp.ərˈeɪ.ʃən ˈsiː.laɪ.ən/The code name for Nazi Germany's planned invasion of the United Kingdom during World War II.
• operational amplifier

  nounVery Low (highly specialized technical term)
  /ˌɒp.əˌreɪ.ʃən.əl ˈæm.plɪ.faɪ.ə/A high-gain, direct-coupled electronic voltage amplifier with differential inputs, used as a building block in analogue circuits.
• operational calculus

  nounVery Low
  /ˌɒp.ərˈeɪ.ʃən.əl ˈkæl.kjə.ləs/A mathematical method that transforms differential equations into simpler algebraic equations, primarily through the use of integral transforms (like the Laplace transform).
• operationalism

  nounC2
  /ˌɒp.ərˈeɪ.ʃən.əl.ɪ.zəm/A philosophical stance which holds that scientific concepts are defined and meaningful only in terms of the specific operations or procedures used to measure or observe them.
• operationalize

  verb-transitiveC1-C2
  /ˌɒp.əˈreɪ.ʃən.əl.aɪz/To put a plan, idea, or theory into practical effect; to make something operational.

Showing 1441–1460 of 3187 words.