ETHOS
In our rhetoric textbook Writing Arguments, Ramage, Bean, and Johnson define "ethos" as follows:
ETHOS (Greek for "character") focuses attention on the writer's (or speaker's) character as it is projected in the message. It refers to the credibility of the writer. Ethos is often conveyed through the writer's investment in his or her claim, through the fairness with which the writer considers alternative views, through the tone and style of the message, and even through the message's professional appearance on paper or screen, including correct grammar, flawless proofreading, and appropriate formats for citations and bibliography. In some cases, ethos is also a function of the writer's reputation for honesty and expertise independent of the message. The impact of ethos on an audience is referred to as the ethical appeal or appeal from credibility. (60-61)