The scarlet letter 'A' worn by Hester Prynne in Nathaniel Hawthorne's novel represents sin, shame, and societal judgment. It serves as a powerful symbol within American Gothic literature, highlighting the themes of guilt and the consequences of transgression in a Puritan society. This emblem of sin illustrates how individuals grapple with their moral failings while navigating the harsh realities of societal expectations and personal redemption.