English Words Starting With O

• oil gland

  nounLow
  /ˈɔɪl ɡlænd/A gland in the skin that produces an oily substance.
• oil hardening

  nounLow
  /ˈɔɪl ˌhɑːdənɪŋ/A heat-treatment process for steel involving heating and then quenching in oil to increase hardness.
• oil meal

  nounC2
  /ˈɔɪl ˌmiːl/The solid residue left after oil is extracted from seeds (such as flax, cottonseed, or soybeans), used as high-protein animal feed or fertilizer.
• oil of catechumens

  nounC1
  /ˌɔɪl əv ˌkatɪˈkjuːmənz/A blessed olive oil used in the Roman Catholic sacrament of baptism for anointing candidates.
• oil of cloves

  nounLow
  /ˈɔɪl əv ˈklaʊvz/A volatile essential oil extracted from clove buds, primarily used for its antiseptic, analgesic, and aromatic properties.
• oil of lavender

  nounLow
  /ɔɪl əv ˈlæv.ən.dər/A fragrant essential oil extracted from lavender flowers, used in aromatherapy, perfumery, and traditional medicine.
• oil of the sick

  nounExtremely Rare / Historical
  /ɔɪl əv ðə sɪk/An archaic term for a medicinal substance extracted from human corpses, considered to have healing properties.
• oil of turpentine

  nounRare/Technical
  /ˈɔɪl əv ˈtɜː.pən.taɪn/A volatile, pungent essential oil distilled from pine tree resin, used as a solvent, paint thinner, and traditionally in medicine.
• oil of vitriol

  nounVery Low (Historical/Technical)
  /ˌɔɪl əv ˈvɪtrɪəl/An archaic term for concentrated sulfuric acid (H₂SO₄).
• oil of wintergreen

  nounLow frequency / Specialist
  /ˌɔɪl əv ˈwɪntəɡriːn/A natural essential oil, or its synthetic equivalent (methyl salicylate), with a strong, minty aroma, extracted from the wintergreen plant or produced synthetically.
• oil paint

  nounC1
  /ˈɔɪl ˌpeɪnt/A type of paint in which pigment is suspended in a drying oil, typically linseed oil.
• oil painting

  nounB2
  /ˈɔɪl ˌpeɪntɪŋ/A picture painted using oil-based paints on a canvas or other surface.
• oil palm

  nounLow frequency (Technical/Agricultural/Business context)
  /ˈɔɪl ˌpɑːm/A tropical palm tree, especially Elaeis guineensis, cultivated for its fruit, which yields palm oil and palm kernel oil.
• oil pan

  nounC1
  /ˈɔɪl ˌpæn/The metal dish-shaped reservoir mounted under the engine block of a vehicle, which holds the engine oil.
• oil patch

  nounB2
  /ˈɔɪl ˌpætʃ/A region where oil is extracted, typically by drilling wells.
• oil rig

  nounB2
  /ˈɔɪl ˌrɪɡ/A large structure with equipment for drilling wells to extract petroleum or natural gas from the earth or seabed.
• oil rivers

  nounplural-nounC2 / Very Low
  /ˈɔɪl ˌrɪv.əz/A historical term referring to the network of creeks, rivers, and estuaries in the Niger Delta region of Nigeria, which was central to the palm oil trade during the 19th and early 20th centuries.
• oil sand

  nounLow in general English; high in technical, energy, and Canadian context.
  /ˈɔɪl ˌsænd/A naturally occurring mixture of sand, clay, water, and bitumen.
• oil shale

  nounC2
  /ˈɔɪl ʃeɪl/a fine-grained sedimentary rock containing kerogen, a solid organic material that can be heated to release liquid hydrocarbons (oil).
• oil slick

  nounC1
  /ˈɔɪl slɪk/A thin, visible film of oil floating on the surface of a body of water.

Showing 701–720 of 3187 words.