- The definition of a scarlet letter is an identifying mark or brand placed on someone who has committed adultery.
An example of a scarlet letter is the Puritan woman in Nathaniel Hawthorne's 1850 book The Scarlet Letter who cheated on her husband and had to wear a red A.
scarlet letter definition by Webster's New World
a scarlet letter A formerly worn by a person convicted of adultery
Origin: ; from the novel The Scarlet Letter (1850) by Nathaniel Hawthorne