First attested in 1807. Shortening of napló könyv (“journal book”), from the archaic napol (“to spend the day somewhere for a certain reason”) + -ó (present participle suffix), from nap (“day”) + -ol (verb-forming suffix). Its formation was also influenced by other languages. Compare German Tagebuch (“journal”) and French journal. Created during the Hungarian language reform, which took place in the 18th–19th centuries.