1. A passage containing accidentally reduplicated syllables, letters, etc.: "Although the secretary had a terrible headache that day, her boss made her type up the letter he had dictated to her earlier. After reading it again, she found many dittographs which appeared throughout the last paragraph which had to be corrected."
2. A letter or word that is repeated unintentionally in writing or when copying written contents: "While Mary was reading through her thesis, she found some mistakes, including dittographs which somehow reappeared on every page!"