Warning: I'm not telling you the answer. You're going to work for it.
When we get started in Ethics, we run into the term "energies" throughout the writings of Aristotle. In English, we think of "energy" as a power to do so something, but we will quickly see that that idea doesn't work when reading Aristotle.
Of course, when we're reading English translations, we have to remember that the original language was Greek. Thankfully, our translator, Thomas Taylor is a true Greek expert and is a philosopher who takes words seriously. Here's the Greek work in the dictionary:
What you can see is that, even in the dictionary, this is a word that is difficult to define.
Now, it's easy to just find a quick answer and ignore the real issue: this is an important word that Aristotle uses with a meaning we must study to understand. We will not find the answer in a dictionary. We must patiently read Aristotle and collect all the information we can until we are able to understand this word as Aristotle uses it.
Therefore, as we read, whenever we encounter the word, I will ask you about it in your comprehension questions. Over time, we will establish, based on Aristotle's own writing, the meaning of this important word. More importantly, you will learn how to establish the meanings of words because the dictionary isn't always right.