Hamartia refers to a character's fatal flaw or error of judgment that ultimately leads to their downfall, as described by Aristotle in his work Poetics. Aristotle defined hamartia as a mistake made by a character, often due to ignorance, that sets in motion tragic events. Examples of hamartia include Othello's jealousy and pride that Iago exploits, Macbeth's ambition that drives him to murder, and Oedipus' short temper that leads to hasty decisions causing his downfall. Hamartia is best understood as a mistake or wrong step taken in ignorance, rather than an inherent character flaw.