[n] an imaginative lively style (especially style of writing); "his writing conveys great energy"
[n] enterprising or ambitious drive; "Europeans often laugh at American energy"
[n] an exertion of force; "he plays tennis with great energy"
[n] the federal department responsible for maintaining a national energy policy; created in 1977
[n] (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"
[n] a healthy capacity for vigorous activity; "jogging works off my excess energy"; "he seemed full of vim and vigor"