A measure of energy is the unit we use to "measure" it. There are a number of forms you may find energy in like fuel, food, fire, etc. Energy is measured in different units by different industries or countries. Scientists also use different units to measure energy according to what they are measuring.

For instance, if you want to measure energy stored in food, you use the calorie, but if you want to measure the energy you need to lift a rock from the ground, you use the Joule. You can also measure the energy that a refrigerator consumes, then you use the Watt

I took the following units of energy from this link

Atmosphere is the unit for measuring pressure.
Calorie is the unit for measuring how much energy you get from food.
Joule is the unit for measuring work or energy.
Kilowatt-hour is the unit for measuring electrical energy. The written abbreviation is kWh.
Newton is the unit for measuring force.
Photon is the unit of energy in the form of light.
Quantum is the unit used for measuring very small amounts of energy.
Therm is the unit for measuring heat, containing 100,000 British Thermal Units.

All units of energy can be converted to the same unit of energy.