1.(physics) 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.an exertion of force;
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