To epitomize something is to be a very typical example of it — to show, in one person or one thing, what that idea is like. A film can epitomize a decade; a habit can epitomize a whole way of working. It is a little formal, more at home in essays and reviews than in chat. American spelling uses -ize; British writers often use epitomise. Same word. Though actually, older academic English also used it to mean “make a short summary of,” because an epitome was once an abridged book. That sense is rare now. For learners, the living meaning is “to be the typical example.”