Vocabulary What does 十二月 (じゅうにがつ) mean? 十二月 (じゅうにがつ) means December. Quick factsReadingじゅうにがつLevel (estimated, JLPT framework)N5 十二月じゅうにがつN5 · estimated, JLPT frameworkDecemberKanji in this word十ten; the number 10二two; the number 2月month; moon