Final answer:
Ethos is an appeal to ethics that helps establish the credibility of the writer or speaker.
Step-by-step explanation:
Ethos is an appeal to ethics, which helps establish the writer's or speaker's credibility. It often invokes the speaker's character and qualifications on the subject. The speaker's authority or credibility can be built through prior credibility, appeal to authority, or earned credibility during the speech itself. Aristotle emphasized that a speaker must be credible or ethical to persuade the audience.