Ethos comes from the Ancient Greek ἦθος (ēthos), meaning "character" or "custom," used in rhetoric since the 4th century BCE to refer to the credibility or ethical appeal of a speaker.
The characteristic spirit, moral values, or beliefs of a person, group, or culture.
From Greek 'ēthos' (ἦθος), meaning 'character, disposition, moral nature, custom, habit,' from PIE *swédʰh₁os (custom, habit), from the root *swedʰ- (custom, one's own character). Aristotle used the term centrally in his 'Rhetoric,' where 'ēthos' is one of three modes of persuasion (alongside 'logos' and 'pathos'): the speaker's character as perceived by the audience. In the 'Nicomachean Ethics,' Aristotle distinguished 'ēthos' (moral character, formed by habit) from 'diánoia' (intellectual character, formed by teaching). The Greek word also gave 'ethikós' (relating to character — whence 'ethics' and 'ethical'). The PIE root *swedʰ- also produced Latin
In rhetoric, 'ethos' refers to the credibility of the speaker, which is one of the three modes of persuasion alongside pathos and logos. Its philosophical usage has influenced various fields, including ethics and sociology.