English Reference
noun

energy

n.
US /ˈɛnɝdʒi/ UK /ˈɛnədʒi/ en·er·gy UK spelling energies

  1. 01 A2 Elementary

    the strength and power you have to do things without getting tired.

    the capacity for vigorous activity or the exertion of power.

    Simple

    I usually have more energy in the morning after a good sleep.

    In context

    The young volunteers brought a great deal of energy to the project, completing the renovation weeks ahead of schedule.

    lethargyfatigue
  2. 02 A2 Elementary

    power from things like oil, coal, or the sun that we use for light and heat.

    usable power derived from physical or chemical resources, especially to provide light and heat or to work machines.

    Simple

    The government is trying to use more green energy like wind and solar power.

    In context

    The industrial sector consumes a significant percentage of the nation's total energy, leading to calls for more efficient manufacturing processes.

  3. 03 B2 Upper Intermediate AcademicTechnical Science

    the ability of a physical system to do work.

    the property of matter and radiation which is manifest as a capacity to perform work, such as causing motion or interaction.

    Simple

    In physics, we learned that energy cannot be destroyed, only changed.

    In context

    Kinetic energy is the energy an object possesses due to its motion, calculated as one-half of its mass times the square of its velocity.

  4. 04 B2 Upper Intermediate Informal

    the feeling or mood that a person or place gives you.

    the perceived emotional quality or atmosphere emanating from a person, place, or situation.

    Simple

    I didn't like the energy in that room; everyone seemed very angry.

    In context

    The team's collective energy shifted from anxiety to determination as soon as the captain delivered her pre-match speech.

  5. 05 B1 Intermediate Informal Computing

    a limited number of points a character can use to perform actions in a game.

    a quantifiable resource in game mechanics that limits the number of actions a player or unit can perform within a specific timeframe.

    Simple

    My character ran out of energy, so I had to wait for it to refill before attacking again.

    In context

    Players must manage their energy bars carefully, as high-damage abilities consume more resources than standard defensive maneuvers.

Usage energy security · energy costs · energy bills


From Middle French énergie, from Late Latin energia, from Ancient Greek ἐνέργεια (enérgeia, “activity”), from ἐνεργός (energós, “active”), from ἐν (en, “in”) + ἔργον (érgon, “work”). The sense in physics was coined by English polymath Thomas Young in 1802 in his lectures on Natural Philosophy.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Ancient Greek ἐνέργεια
Level A2 · Elementary
Frequency Very common
Updated