English Words Starting With O

• orbital

  adjectivenounB2
  /ˈɔː.bɪ.təl/Relating to or describing an orbit, the curved path of an object around a star, planet, or moon.
• orbital angular momentum

  nounLow
  /ˈɔː.bɪ.təl ˈæŋ.ɡjə.lər məʊˈmen.təm/In quantum mechanics, the angular momentum of a particle, such as an electron, due to its orbital motion around a nucleus or central point.
• orbital index

  nounVery Low (C2+)
  /ˈɔː.bɪ.təl ˈɪn.deks/A scientific ratio expressing the relationship between the width and length of the bony eye socket (orbit).
• orbital sander

  nounLow
  /ˌɔː.bɪ.təl ˈsæn.dər/A handheld power tool with a circular sanding pad that moves in small elliptical orbits, used for smoothing wood and other surfaces.
• orbital velocity

  nounLow (Technical/Scientific)
  /ˈɔː.bɪ.təl vəˈlɒs.ə.ti/The speed required for a satellite or celestial body to maintain a stable orbit around a larger body, balancing gravitational pull and centrifugal force.
• orbitale

  nounC1
  /ˈɔː.bɪ.təl/Relating to or describing an orbit; the path of an object around a star, planet, or moon.
• orbiteer

  verb-intransitiveverb-transitiveExtremely Rare / Obsolete
  /ˈɔː.bɪ.tɪə/A term historically used, but not standardized, to denote a person who travels in or operates an orbital craft; a coiner or user of a novel word for an astronaut or cosmonaut.
• orbiter

  nounC2
  /ˈɔː.bɪ.tər/An object or vehicle that travels in an orbit, especially an artificial satellite or spacecraft designed to orbit a celestial body without landing on it.
• orbiting astronomical observatory

  nounLow
  /ˈɔːbɪtɪŋ ˌæstrəˈnɒmɪkəl əbˈzɜːvətri/A type of satellite specifically designed and placed in Earth's orbit to conduct astronomical observations of stars, galaxies, and other celestial objects from outside Earth's atmosphere.
• orbiting geophysical observatory

  nounVery Low
  /ˈɔː.baɪ.tɪŋ ˌdʒiː.əʊˈfɪz.ɪ.kəl əbˈzɜː.və.tri/A series of NASA satellites launched in the 1960s designed to study Earth's space environment.
• orbiting solar observatory

  nounLow
  /ˈɔː.baɪ.tɪŋ ˈsəʊ.lə ɒbˈzɜː.və.tri/A scientific satellite specifically designed and launched to observe the Sun from space.
• orc

  nounB2
  /ɔːk/A mythical creature, often portrayed as large, aggressive, and grotesquely humanoid, typically serving evil forces in fantasy literature and gaming.
• orca

  nounB2
  /ˈɔː.kə/A large, black-and-white predatory marine mammal of the dolphin family, also known as a killer whale.
• orcadian

  adjectivenounLow
  /ɔːˈkeɪ.di.ən/Relating to the Orkney Islands or their inhabitants.
• orcagna

  nounVery Low
  /ɔːˈkɑːnjə/A proper noun referring to the nickname of the 14th-century Italian painter, sculptor, and architect Andrea di Cione.
• orcein

  nounVery Rare
  /ˈɔːsiɪn/A reddish-brown dye obtained from lichens, used in histology.
• orchard

  nounB2
  /ˈɔːtʃəd/An area of land dedicated to the cultivation of fruit or nut trees.
• orchard bush

  nounVery low / Rare
  /ˈɔːtʃəd bʊʃ/A wild, dense shrub, typically hawthorn, growing in hedgerows or at the edge of woodland, distinct from cultivated orchard trees.
• orchard grass

  nounC1+ / Specialized
  /ˈɔː.tʃəd ɡrɑːs/A perennial grass species (Dactylis glomerata) commonly grown for forage and hay, often found in meadows and pastures.
• orchard oriole

  nounLow
  /ˈɔː.tʃəd ˈɔː.ri.əʊl/A small North American songbird (Icterus spurius) with black and chestnut plumage in the male, often found in open woodlands and orchards.

Showing 1701–1720 of 3187 words.