Energy Manipulation was the ability to manipulate energy. One can use this ability to make energy constructs. Energy constructs, as the name makes plain, were constructs made from energy. Members of the Green Lantern Corps used power rings to create energy constructs with nothing more than their own will power.
Other abilities energy manipulators possessed were Energy Absorption and Energy Projection. A few characters had the ability to negate energy, which could take away another person's super powers, scramble radar, sonar or remove power from a building, creating a blackout. Generally characters with this ability could only negate energy, and couldn't manipulate energy in any other way but that.
Other characters had the ability to transfer the energy from one thing or person to another, thereby stealing the energy from one person and giving that stolen energy to another. This ability was called Energy Transference.