What is greek name for energy?

There isn't one single Greek word that perfectly translates to the modern scientific concept of "energy." The ancient Greeks didn't have a concept that encompassed all forms of energy as we understand it today. They had words for related ideas, such as:

* δύναμις (dynamis): This word is closer to "power" or "potential" than "energy." It refers to capacity, ability, or strength. It's a closer ancestor to the word "dynamics" than a direct equivalent of "energy."

* ἐνέργεια (energeia): Interestingly, this word *is* the root of our word "energy." However, in ancient Greek, it meant something more like "activity," "operation," or "effectiveness" rather than the scientifically defined quantity. Aristotle used it to describe the actuality of something as opposed to its potentiality (dynamis).

So, while ἐνέργεια (energeia) is etymologically the source of our word, it doesn't directly translate as the modern scientific concept of energy. There's no single perfect Greek equivalent.