English Words Starting With O

• orris

  nounC2+ / Very Low Frequency
  /ˈɒrɪs/The dried, fragrant rootstock of certain irises, used historically in perfumery, medicine, and as a powdered fixative.
• orrisroot

  nounC2
  /ˈɒr.ɪs.ruːt/The fragrant rhizome of certain iris species (especially Iris germanica, I. pallida, and I. florentina), dried and used in perfumery, herbal medicine, and as a fixative.
• orsha

  nounVery Low
  /ˈɔːʃə/A proper noun referring to the city of Orsha, an industrial centre in eastern Belarus.
• orsini

  nounVery rare
  /ɔːˈsiːni/A prominent Italian noble family, historically one of the most influential princely houses in medieval and Renaissance Rome.
• orsk

  nounExtremely rare / Non-existent
  The word 'orsk' does not exist in standard English dictionaries. It appears to be a non-standard term, possibly a typo, proper noun, or invented word.
• orson

  nounVery Low
  /ˈɔːs(ə)n/A male given name.
• ort

  nounArchaic/Low
  /ɔːt/A scrap or fragment of food left after a meal, originally referring specifically to table scraps.
• ortanique

  nounLow/Obscure
  /ˌɔː.təˈniːk/A citrus fruit hybrid, a cross between an orange and a tangerine (mandarin).
• ortega

  nounRare
  /ɔːˈteɪɡə/A specific genus of butterfly (family Nymphalidae) found in the Americas.
• ortega saavedra

  nounLow
  /ɔːˈteɪɡə sɑːəˈveɪdrə/A Spanish surname referring to a specific Nicaraguan political family, most notably Daniel Ortega Saavedra, the long-standing president of Nicaragua.
• ortega y gasset

  nounLow
  /ɔːˌteɪɡə iː ɡæˈset/A Spanish philosopher and essayist.
• ortegal

  nounExtremely Rare / Obsolete
  /ˈɔːtɪɡ(ə)l/An obsolete term for a specific size or type of painting or canvas, roughly equivalent to 46 x 38 inches.
• orthicon

  nounVery low (C2/professional technical)
  /ˈɔːθɪkɒn/A type of television camera tube that converts light into an electronic signal.
• ortho-cousin

  nounVery Low / Technical
  /ˌɔː.θəʊ ˈkʌz.ən/A first cousin related through two siblings of the same sex (e.g., one's father's brother's child or mother's sister's child).
• ortho-dichlorobenzene

  nounVery Low
  /ˌɔːθəʊ daɪˌklɔːrəʊˈbɛnziːn/A specific chemical compound consisting of a benzene ring with two chlorine atoms attached at adjacent (1,2-) positions.
• ortho-toluidine

  nounVery Low
  /ˌɔːθəʊˈtɒljʊədiːn/A toxic, colourless to pale yellow aromatic amine, an isomer of toluidine, with the amino group adjacent to the methyl group on the benzene ring. Primarily used in the production of dyes.
• ortho-xylene

  nounRare
  /ˌɔːθəʊ ˈzaɪliːn/An aromatic hydrocarbon isomer of xylene (dimethylbenzene) where the two methyl groups are attached to adjacent carbon atoms on the benzene ring (positions 1 and 2).
• orthoboric acid

  nounLow (Technical)
  /ˌɔːθəʊˌbɔːrɪk ˈæsɪd/A white, crystalline, weak inorganic acid with the chemical formula H₃BO₃, used as an antiseptic, insecticide, flame retardant, and in the manufacture of glass and ceramics.
• orthocenter

  nounC2
  /ˈɔːθəʊˌsɛntə/The point of intersection of the three altitudes of a triangle.
• orthocentre

  nounVery Low
  /ˈɔːθə(ʊ)ˌsɛntə/The point of intersection of the three altitudes of a triangle.

Showing 2041–2060 of 3187 words.