Anagnorisis

The moment of recognition or discovery in a drama when a character passes from ignorance to knowledge—realising a crucial truth about themselves, another character, or their situation. Aristotle considered anagnorisis essential to the best tragedies. The most famous example is Oedipus discovering that he has killed his father and married his mother. The power of anagnorisis lies in its irreversibility: once known, the truth cannot be unknown.