Vocabulary: what is hegemony? What is a hegemon?

Tutoring English, vocabulary is always interesting. The tutor mentions the word hegemony.

The following is according to my understanding.

Hegemony means the ability to coerce others because of superior strength or aggression. A hegemon is one who has such ability.

One hears about hegemony these days, with military powers displaying strength in their local areas, or even using it against rivals.

Source:

Mish, F.C. (editor, 2004). The Merriam-Webster Dictionary. Merriam-Webster, Incorporated.