English Words Starting With A

• atomic energy authority

  nounC1
  /əˌtɒm.ɪk ˈen.ə.dʒi ɔːˈθɒr.ə.ti/A public organization responsible for the oversight, research, regulation, or development of atomic/nuclear energy.
• atomic energy commission

  nounC1
  /əˌtɒm.ɪk ˈen.ə.dʒi kəˌmɪʃ.ən/A specific historical U.S. government agency responsible for the development and control of atomic energy and nuclear weapons.
• atomic heat

  nounVery low (C2/Professional)
  /əˌtɒm.ɪk ˈhiːt/The heat capacity per mole of an element; the product of the specific heat of an element and its atomic weight.
• atomic hydrogen

  nounLow (C1/C2)
  /əˌtɒm.ɪk ˈhaɪ.drə.dʒən/A single, isolated hydrogen atom (H), not bonded to another atom.
• atomic mass

  nounC2
  /əˌtɒmɪk ˈmæs/The mass of a single atom of a chemical element, typically expressed in atomic mass units (amu) or daltons (Da).
• atomic mass unit

  nounC2
  /əˌtɒm.ɪk ˌmæs ˈjuː.nɪt/A standard unit of mass, exactly 1/12 of the mass of a carbon-12 atom.
• atomic number

  nounC1
  /əˈtɒmɪk ˈnʌmbə/The number of protons in the nucleus of an atom, which determines its chemical properties and place in the periodic table.
• atomic pile

  nounLow
  /əˌtɒm.ɪk ˈpaɪl/An early type of nuclear reactor, consisting of a large pile of graphite blocks and uranium used to initiate and sustain a controlled nuclear chain reaction.
• atomic power

  nounC1
  /əˌtɒm.ɪk ˈpaʊ.ər/Power derived from nuclear reactions, specifically from the process of nuclear fission, used to generate electricity.
• atomic structure

  nounC1
  /əˌtɒm.ɪk ˈstrʌk.tʃər/The arrangement and organization of the components of an atom, particularly electrons, protons, and neutrons.
• atomic theory

  nounC1
  /əˌtɒm.ɪk ˈθɪə.ri/The scientific theory that all matter is composed of tiny, indivisible particles called atoms.
• atomic veteran

  nounLow
  /əˌtɒm.ɪk ˈvet.ər.ən/A military service member who was involved in, witnessed, or was present during nuclear weapons testing or the immediate aftermath of their use.
• atomic volume

  nounC2
  /əˌtɒm.ɪk ˈvɒl.juːm/The volume occupied by one mole of atoms of a given element under standard conditions, calculated as the atomic mass divided by the density.
• atomic weight

  nounC1
  /əˌtɒm.ɪk ˈweɪt/The average mass of atoms of an element, measured in atomic mass units (amu), taking into account the relative abundances of its isotopes.
• atomicity

  nounC2
  /ˌæt.əˈmɪs.ə.ti/The state or property of being composed of atoms.
• atomics

  nounC2/Rare
  /əˈtɒm.ɪks/The branch of physics or technology dealing with the structure, properties, and behavior of atoms, especially in relation to the release of nuclear energy.
• atomism

  nounC2
  /ˈæt.ə.mɪ.zəm/A theory that complex systems, ideas, or entities are best understood by breaking them down into their simplest, indivisible components.
• atomization

  nounC1/C2 (Advanced/Proficient)
  /ˌæt.ə.maɪˈzeɪ.ʃən/The process of separating something into isolated, disconnected parts or individuals.
• atomize

  verbverb-intransitiveverb-transitiveC1
  /ˈæt.ə.maɪz/to reduce something to tiny, separate particles or units; to fragment.
• atomizer

  nounC1-C2
  /ˈæt.ə.maɪ.zə(r)/A device that breaks a liquid into a fine spray.

Showing 7781–7800 of 8734 words.