추석

Etymology
, whose meaning is uncertain. There are many theories that try to explain this, one of which suggests that the word 秋夕 (chuseok) originates from the following phrases:
 * Dai De, ed., Dadailiji Volume 3 "Preservation":
 * 三代之禮，天子春朝朝日，秋暮夕月，所以明有別也.
 * According to the rite throughout three generations, the emperor, in a spring morning, worships the sun, and, in an autumn evening, the moon, thus clearly has difference.
 * Pei Yin, ed., The collection of commentaries on the Records of the Grand Historian Volume 12:
 * 集解應劭曰：「天子春朝日，秋夕月，拜日東門之外，朝日以朝，夕月以夕. 」
 * The commentary by Ying Shao reads "The emperor in spring worships the sun, and in autumn the moon, outside the East Gate, worships the sun by the morning, and the moon by the evening."

Proper noun

 * 1) Mid-Autumn Festival, three day harvest festival (August 15 in lunar calendar)