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December (traditional Japanese month name)
The traditional name for the twelfth month. One of the most widely known of the old month names (和風月名). The kanji 師 (master, teacher) + 走 (run) reflect the folk etymology that even Buddhist priests are so busy at year-end that they run around. Still commonly used in modern Japanese, especially in seasonal greetings and media.
Etymology
The folk etymology is that 師 (Buddhist priests/teachers) 走る (run) because December is so busy with year-end Buddhist ceremonies. While this explanation is widely known, the true etymology is uncertain.
Cultural note
師走 is one of the few traditional month names that remains in active everyday use. It evokes the particular busyness of December in Japan: 大掃除 (year-end cleaning), 忘年会 (year-end parties), 年賀状 (New Year's cards), and holiday preparations.