English Words Starting With O

• open caption

  nounC1
  /ˌəʊpən ˈkæp.ʃən/Text displayed on screen during audiovisual content that represents dialogue, sound effects, and other audio information, intended for general viewers rather than specifically for deaf or hard-of-hearing audiences.
• open carry

  nounLow
  /ˌəʊ.pən ˈkær.i/The practice of visibly carrying a firearm in a public place.
• open chain

  nounC1
  /ˌəʊ.pən ˈtʃeɪn/A sequence of interconnected elements (typically atoms in a molecule or businesses in a system) that is not arranged in a ring or closed loop.
• open cheque

  nounC2
  /ˌəʊpən ˈtʃek/A cheque made out to cash, not a named payee, which can be cashed by anyone in possession of it.
• open circuit

  nounC1
  /ˌəʊ.pən ˈsɜː.kɪt/An electrical circuit that is not complete, preventing current from flowing.
• open city

  nounC2/Rare
  /ˌəʊ.pən ˈsɪt.i/A city officially declared demilitarized and undefended in time of war, thus spared from deliberate bombardment under international law.
• open classroom

  nounB2
  /ˌəʊpən ˈklɑːsruːm/A flexible teaching environment without physical partitions between different learning areas, often featuring movable furniture and promoting collaborative, student-centred learning.
• open cluster

  nounC1/C2 (Specialised)
  /ˌəʊ.pən ˈklʌ.stə/A loose, irregularly shaped group of stars that formed from the same giant molecular cloud.
• open college

  nounLow
  /ˌəʊpən ˈkɒlɪdʒ/An educational institution that provides flexible, often remote or part-time courses, typically with fewer entry restrictions than traditional universities.
• open communion

  nounC2
  /ˌəʊ.pən kəˈmjuː.njən/A Christian church's practice of allowing any baptized Christian, regardless of denomination, to receive the Eucharist or Lord's Supper.
• open convention

  nounLow
  /ˌəʊ.pən kənˈven.ʃən/A political event where the party's nominee for president or other major office is not predetermined before the event begins, allowing delegates to vote for any candidate, potentially through multiple ballots.
• open couplet

  nounLow
  /ˌəʊ.pən ˈkʌp.lət/A pair of rhyming lines of poetry (a couplet) where the sense or thought continues into the next line or couplet without a pause or punctuation at the end of the first line.
• open court

  nounC1/C2
  /ˌəʊ.pən ˈkɔːt/A court session that is not held privately but is accessible to the public and the press.
• open cover

  nounC2
  /ˌəʊ.pən ˈkʌ.vər/A noun phrase describing a collection of open sets in a topological space whose union contains a given set.
• open cut

  adjectivenounC1/C2 (specialized technical term)
  /ˌəʊ.pən ˈkʌt/A method of mining where the earth's surface is excavated to access mineral deposits.
• open dating

  nounB2
  /ˌəʊ.pən ˈdeɪ.tɪŋ/A system of printing a date on food packages to indicate when the product should be sold by or used by for best quality.
• open day

  nounMedium
  /ˌəʊ.pən ˈdeɪ/A day when an institution, such as a school, university, or company, opens its doors to the public, especially prospective students or customers, to showcase its facilities, activities, and offerings.
• open diapason

  nounRare
  /ˌəʊp(ə)n ˌdʌɪəˈpeɪz(ə)n/A principal organ stop of full, foundational, unimpeded tone, typically of eight-foot pitch.
• open die

  nounLow
  /ˈəʊ.pən daɪ/A metalworking or forging die that is not fully enclosed, allowing the workpiece to be shaped on only two or three sides with limited restriction to lateral flow of material.
• open door

  adjectivenounB2
  /ˌəʊ.pən ˈdɔː(r)/A policy or situation permitting free access, entry, or opportunity, often used figuratively to denote unrestricted availability.

Showing 1341–1360 of 3187 words.