Ethos refers to an appeal to credibility. This means that a person talks about his abilities, experience, accomplishments, etc. in order to persuade an audience of a particular position. Ethos is one of the most common rhetorical devices, along with pathos and logos. In this case, the nurse is mentioning the fact that she has been a nurse for over twenty years in order to persuade people of her knowledge and the validity of her opinion.
