Rajōmon (羅城門?), also called Rashōmon (羅生門?), was the gate built at the southern end of the monumental Suzaku Avenue in the ancient Japanese cities of Heijō-kyō (Nara) and Heian-kyō (Kyoto), in accordance with the Chinese grid-patterned city layout. At the other far north-end of Suzaku Avenue, one would reach the Suzakumon Gate, the main entrance to the palace zone. As of 2007, the southern end of Suzaku Avenue and the possible remainder of the equivalent gate in Fujiwara-kyō (Kashihara) are yet to be discovered.
The gate's name in modern Japanese is Rajōmon. Rajō (羅城) refers to city walls and mon (門) means "gate," so Rajōmon signifies the main city gate. Originally, this gate was known as Raseimon or Raiseimon, using alternate readings for the kanji in the name. The name Rashōmon, using the kanji 羅生門 (which can also be read Raseimon), was popularized by a noh play Rashōmon (c.1420) written by Kanze Nobumitsu (1435–1516).
The modern name, Rajōmon, uses the original kanji (羅城門 rather than 羅生門) and employs the more common reading for the second character (jō instead of sei).