English Words Starting With O

• oncogenicity

  nounC2/Technical
  /ˌɒŋkəʊdʒəˈnɪsəti/The capacity of an agent (like a virus, chemical, or radiation) to cause cancer.
• oncology

  nounC1
  /ɒŋˈkɒlədʒi/The branch of medicine that deals with the study, diagnosis, treatment, and prevention of cancer.
• oncoming

  adjectivenounB2
  /ˈɒnˌkʌm.ɪŋ/Moving towards one; approaching.
• oncornavirus

  nounVery low
  /ˌɒŋkɔːnəˈvaɪrəs/An obsolete taxonomic term for a group of RNA viruses that can cause cancer (oncogenesis).
• oncost

  nounLow
  /ˈɒnkɒst/An additional or incidental cost; an overhead or expense incurred in the course of business that cannot be directly attributed to a specific product or service.
• ondaatje

  nounVery Low
  /ɒnˈdɑːtʃi/A proper noun, specifically a surname of Sri Lankan Burgher origin.
• ondes martenot

  nounC2
  /ɒ̃d mɑːtənəʊ/A monophonic electronic musical instrument invented in 1928 by Maurice Martenot, known for its expressive, ethereal sound controlled by a keyboard and a ribbon.
• ondine

  nounLow
  /ɒnˈdiːn/A mythological water nymph or female water spirit, especially in German and French folklore.
• onding

  nounVery Low
  /ˈɒndɪŋ/A heavy or continuous fall of rain or snow; a downpour or heavy snowfall.
• ondo

  nounExtremely Low / Obsolete / Technical
  /ˈɒn.dəʊ/A wave, surge, or billow; also, in specific contexts, the first of a pair of waves (nidan dōshi) in Japanese grammar.
• ondograph

  nounVery Rare (Obsolete Technical Term)
  /ˈɒndəɡrɑːf/An instrument for automatically recording the shapes and waveforms of alternating electric currents.
• one old cat

  nounVery Low (archaic/historical)
  /wʌn əʊld ˈkæt/A simple, informal bat-and-ball game, often played by children, that is a simplified precursor to baseball.
• one thousand guineas

  nounLow
  /wʌn ˈθaʊz(ə)nd ˈɡɪniːəz/A sum of £1,050, referring to the historical coin (the guinea), which was valued at one pound and one shilling.
• one-a-cat

  nounRare / Archaic
  /ˌwʌn.ə.ˈkæt/A name for a children's game or activity, also used as a counting-out rhyme.
• one-acter

  nounC1
  /ˌwʌn ˈæk.tər/A short play consisting of only one act.
• one-armed bandit

  nounlow
  /ˌwʌn ɑːmd ˈbændɪt/A slot machine, typically operated by pulling a lever (the 'arm'), used for gambling.
• one-bagger

  nounLow
  /ˈwʌn ˌbæɡ.ə/A hit in baseball that allows the batter to reach first base safely.
• one-base hit

  nounLow
  /ˌwʌn beɪs ˈhɪt/A batted ball in baseball that allows the batter to safely reach first base.
• one-drop rule

  nounvery low
  /ˈwʌn drɒp ˌruːl/A historical social and legal principle of racial classification in the United States which asserted that any person with even one ancestor of sub-Saharan African ancestry ("one drop" of "black blood") was considered black.
• one-eighty

  nounB2-C1
  /ˌwʌn ˈeɪti/A complete reversal or change of direction, attitude, or opinion.

Showing 1161–1180 of 3187 words.