English Words Starting With H

• heat lamp

  nounC1
  /ˈhiːt ˌlæmp/An electric lamp designed to produce infrared radiation, used primarily for providing warmth.
• heat lightning

  nounLow
  /ˈhiːt ˌlaɪt.nɪŋ/Silent flashes of lightning seen on the horizon on hot summer nights, not accompanied by thunder.
• heat of combustion

  nounTechnical / C2+
  /ˈhiːt əv kəmˈbʌs.tʃən/The amount of heat energy released when a specified amount of a substance undergoes complete combustion with oxygen.
• heat of condensation

  nounLow frequency
  /ˌhiːt əv ˌkɒn.denˈseɪ.ʃən/The thermal energy released when a vapour or gas changes phase into a liquid at a constant temperature and pressure.
• heat of formation

  nounVery Low
  /ˌhiːt əv fɔːˈmeɪʃən/The change in enthalpy when one mole of a compound is formed from its constituent elements in their standard states.
• heat of fusion

  nounLow
  /ˈhiːt əv ˈfjuːʒən/The amount of energy required to change a substance from solid to liquid state at its melting point without changing its temperature.
• heat of reaction

  nounC2
  /hiːt əv riˈækʃən/The amount of heat energy released or absorbed during a chemical reaction at constant pressure.
• heat of solidification

  nounLow/Very Low
  /ˈhiːt əv səˌlɪdɪfɪˈkeɪʃən/The amount of heat energy released when a unit mass of a liquid changes into a solid at its freezing point, at constant temperature and pressure.
• heat of solution

  nounC1/C2
  /ˌhiːt əv səˈluːʃən/The overall enthalpy change when one mole of a substance dissolves completely in a solvent at constant pressure.
• heat of sublimation

  nounLow
  /hiːt əv ˌsʌblɪˈmeɪʃ(ə)n/The amount of energy required to change one mole of a substance from solid to gas at a constant temperature and pressure.
• heat of vaporization

  nounC2
  /ˌhiːt əv ˌveɪ.pər.aɪˈzeɪ.ʃən/The amount of heat energy required to change a unit mass of a substance from a liquid to a gas at constant temperature and pressure.
• heat prostration

  nounLow-to-Medium
  /hiːt prɒˈstreɪʃ(ə)n/A serious physical condition caused by overexposure to high temperatures, resulting in exhaustion, dizziness, weakness, and potentially collapse, but not reaching the stage of life-threatening heatstroke.
• heat pump

  nounC1
  /ˈhiːt ˌpʌmp/A device that transfers heat from a cooler area to a warmer area, using electrical energy, to provide heating or cooling for a building.
• heat rash

  nounMedium-High (Common in medical, parenting, and everyday summer contexts)
  /ˈhiːt ˌræʃ/A skin condition characterized by small, itchy red bumps, caused by blocked sweat glands and exacerbated by heat, humidity, or excessive sweating.
• heat reservoir

  nounC1
  /ˈhiːt ˌrɛz.ə.vwɑː/A body or system that can absorb or supply a significant amount of heat without undergoing a significant change in temperature.
• heat shield

  nounC1/C2
  /ˈhiːt ʃiːld/A device designed to protect a structure from excessive heat, especially by reflecting or absorbing thermal energy.
• heat sink

  nounC1
  /ˈhiːt ˌsɪŋk/A device or substance that absorbs and dissipates unwanted heat from another object to prevent overheating.
• heat wave

  nounB1
  /ˈhiːt ˌweɪv/A prolonged period of abnormally and uncomfortably hot weather, often with high humidity.
• heat-moon

  nounRare
  /ˈhiːt ˌmuːn/A period of extreme cold during the winter in which the moon is visible.
• heat-seal

  verb-transitiveC2 (Very low frequency, highly technical/specific)
  /ˈhiːt ˌsiːl/To join two materials (typically plastic or polymer) by applying heat and pressure to create a permanent bond.

Showing 1861–1880 of 5990 words.