English Words Starting With Q

• quantum jump

  nounLow in everyday conversation, medium in academic and technical registers.
  /ˈkwɒntəm dʒʌmp/A sudden and significant change or leap, especially in quantum physics where an electron transitions between discrete energy levels.
• quantum leap

  nounmedium
  /ˈkwɒntəm liːp/a sudden, dramatic, and significant change or advance, especially in science, technology, or thought.
• quantum mechanics

  nounLow
  /ˈkwɒntəm mɪˈkanɪks/The branch of physics that describes the behaviour of matter and energy at the atomic and subatomic scale, where physical quantities often take discrete values (quanta).
• quantum number

  nounLow
  /ˈkwɒntəm ˈnʌmbə/One of a set of integer or half-integer numbers that specify the state of a quantum system (e.g., an electron in an atom) and its properties, such as energy, angular momentum, and spin.
• quantum optics

  nounC2+ (Very Low Frequency outside specialized technical contexts)
  /ˈkwɒntəm ˈɒptɪks/The branch of physics that studies light and its interactions with matter at the level of individual photons and atoms.
• quantum state

  nounLow in general usage, high in academic and technical contexts.
  /ˈkwɒntəm steɪt/The complete description of a quantum system, encompassing all probabilistic information about its properties such as position, momentum, and spin.
• quantum statistics

  nounC2
  /ˈkwɒntəm stəˈtɪstɪks/A branch of quantum mechanics and statistical mechanics dealing with the statistical behavior of large ensembles of identical particles, where the indistinguishability and quantum nature of particles lead to fundamentally different statistical distributions (Bose–Einstein or Fermi–Dirac) than classical Maxwell–Boltzmann statistics.
• quantum system

  nounLow (in general discourse), Very High (in physics, quantum computing, and certain technical fields).
  /ˈkwɒn.təm ˈsɪs.təm/A physical system (a particle, atom, molecule, or larger assembly) whose behavior is governed by the laws of quantum mechanics, meaning its properties (like energy, position, momentum) are quantized and it can exist in superpositions of states.
• quantum teleportation

  nounLow
  /ˈkwɒntəm ˌtɛlɪpɔːˈteɪʃən/The theoretical transfer of quantum information between particles at a distance without physical movement of the particles themselves.
• quantum theory

  nounC1
  /ˈkwɒn.təm ˈθɪə.ri/A fundamental theory in physics describing the behavior of matter and energy at the smallest scales, where energy exists in discrete, indivisible units called quanta.
• quantz

  nounExtremely Low
  /kvants/a surname, most notably associated with the 18th-century German flautist and composer Johann Joachim Quantz.
• quanzhou

  nounLow Frequency (Proper Noun). Common in historical, geographical, and cultural texts; uncommon in everyday conversation outside specific contexts.
  /ˈtʃwænˈdʒəʊ/A major prefecture-level city and historic port in Fujian Province, southeastern China, famous for its maritime history and cultural heritage.
• quao

  nounExtremely rare / Not in standard dictionaries
  A non-existent or erroneous word in standard English. Possibly a misspelling or a highly obscure, fabricated term.
• quapaw

  nounLow (specialist/historical)
  /ˈkwɑːpɔː/A member of a Native American people originally from the Ohio River valley, later settled in what is now Arkansas.
• quarantine

  nounverbverb-transitiveC1
  /ˈkwɒr.ən.tiːn/A period of isolation imposed to prevent the spread of disease or contamination.
• quarantine anchorage

  nounC2 (Proficient User - Low Frequency)
  /ˈkwɒr.ən.tiːn ˈæŋ.kər.ɪdʒ/A designated maritime area where ships arriving from foreign ports are required to anchor and undergo health inspections to prevent the spread of contagious disease.
• quarantine flag

  nounC2
  /ˈkwɒr.ən.tiːn ˌflæɡ/A yellow flag (historically the "Lima flag") flown by a vessel to signal that it is requesting pratique (clearance from health authorities) or that it has health issues on board, meaning it is under quarantine.
• quark

  nounC1
  /kwɔːk/A fundamental subatomic particle that is a basic constituent of matter, combining to form hadrons like protons and neutrons.
• quark model

  nounC2 (Very low frequency, specialist term)
  /kwɑːk ˈmɒd(ə)l/A theoretical framework in particle physics proposing that protons, neutrons, and other hadrons are composed of smaller, fundamental particles called quarks.
• quark star

  nounC2 / Extremely Rare / Technical
  /ˈkwɑːk ˌstɑː/A hypothetical type of compact stellar remnant composed of quark matter, believed to form when the pressure inside a neutron star is sufficient to break down neutrons into their constituent quarks.

Showing 221–240 of 698 words.