Ethos refers to the credibility or ethical appeal that a speaker or writer brings to their argument. It is one of the three modes of persuasion identified by the ancient Greek philosopher Aristotle, alongside Pathos (emotional appeal) and Logos (logical appeal). Ethos is crucial in establishing trust and authority, making the audience more likely to accept the argument presented. In practical terms, ethos can be developed through the speaker's reputation, expertise, and moral character. For instance, a doctor discussing health issues will have a stronger ethos than someone without medical training. This credibility helps to persuade the audience and enhances the overall effectiveness of communication.