English Words Starting With O

• open-source

  adjectivenounC1/C2
  /ˌəʊ.pən ˈsɔːs/Refers to software whose source code is made freely available for use, modification, and redistribution by the public.
• opencast mining

  nounC1-C2
  /ˈəʊ.pən.kɑːst ˈmaɪ.nɪŋ/A method of extracting minerals from the earth by digging large pits on the surface rather than tunneling underground.
• opener

  nounB1
  /ˈəʊpənə(r)/A device, tool, or person that opens something.
• opening

  adjectivenounHigh (C1)
  /ˈəʊp(ə)nɪŋ/An empty space, gap, or hole; a beginning or initial part of something; the act of making something open or accessible.
• opening night

  nounB2
  /ˈəʊpənɪŋ naɪt/The first public performance of a play, film, or other show.
• opening time

  nounB1
  /ˈəʊ.pən.ɪŋ ˌtaɪm/The specific hour at which a business, institution, or venue begins operating and becomes accessible to the public.
• openness

  nounC1
  /ˈəʊ.pən.nəs/The quality or state of being open, honest, and communicative; lack of secrecy or concealment.
• openwork

  nounC1
  /ˈəʊ.pən.wɜːk/Decorative work with a pattern of openings or holes.
• opera

  nounB1
  /ˈɒp(ə)rə/A dramatic work set to music for singers and instrumentalists, typically performed in a theatre.
• opera bouffe

  nounC2
  /ˌɒp(ə)rə ˈbuːf/A short, humorous opera, typically with a farcical or satirical plot.
• opera buffa

  nounC2
  /ˈɒp(ə)rə ˈbʊfə/A form of Italian comic opera, characterized by everyday characters, spoken dialogue, and humorous, often satirical plots.
• opera cloak

  nounLow
  /ˈɒp(ə)rə ˌkləʊk/A formal, full-length cloak, often elaborately decorated, worn over evening dress to attend the opera or similar formal evening events.
• opera comique

  nounC2
  /ˌɒp(ə)rə kɒˈmiːk/A genre of French opera containing spoken dialogue and often a happy ending, originating in 18th-century Paris.
• opera glasses

  plural-nounC1
  /ˈɒp(ə)rə ˌɡlɑːsɪz/A small, lightweight, hand-held binoculars used to see the stage more clearly in a theater, especially an opera house.
• opera hat

  nounC2
  /ˈɒp(ə)rə hæt/A tall, black, collapsible silk top hat traditionally worn by men in formal evening dress.
• opera house

  nounB1
  /ˈɒp(ə)rə ˌhaʊs/A large theatre building specifically designed and used for performances of opera.
• opera seria

  nounC2
  /ˌɒp(ə)rə ˈsɪərɪə/A genre of Italian opera from the 18th century characterized by serious, often mythological or historical subjects, formal structure, and elaborate vocal display.
• opera window

  nounRare
  /ˈɒp.ər.ə ˈwɪn.dəʊ/A small, fixed, often oval or rectangular window positioned in the C-pillar of a car, behind the rear side window.
• operagoer

  nounLow frequency (C1/C2 level vocabulary)
  /ˈɒp(ə)rəˌɡəʊə/A person who attends performances of operas.
• operand

  nounC2 / Very low frequency
  /ˈɒp.ər.ænd/A quantity or object on which a mathematical or logical operation is performed.

Showing 1421–1440 of 3187 words.