What does ENERGY mean?

noun

1. (physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs“energy can take a wide variety of forms”
2. forceful exertion“he plays tennis with great energy”
3. enterprising or ambitious drive“Europeans often laugh at American energy”
4. an imaginative lively style (especially style of writing)“his writing conveys great energy”
5. a healthy capacity for vigorous activity“jogging works off my excess energy”
6. any source of usable power“the DOE is responsible for maintaining the energy policy”