The Japanese word for month is
月

つき - tsuki

month

Japanese Definition

月
1. n. the moon
(syn-lite, ja, sc=Jpan, 太陰, tr=taiin, ムーン, tr2=mūn)
2. n. (astronomy) a natural satellite
3. n. moonlight, moonbeam
(syn-lite, ja, sc=Jpan, 月光, tr=gekkō, 月影, tr2=tsukikage)
4. n. a (m-lite, ja, sc=Jpan, 家紋, tr=kamon, , family crest) with various designs of the moon
5. n. (tarot) the Moon, the eighteenth trump or major arcana card in most traditional Tarot decks
6. n. a month
(syn-lite, ja, sc=Jpan, 月経, tr1=gekkei, 月の物, tr2=tsuki no mono)
7. suffix. month of the year
8. affix. moon
9. affix. month
10. affix. Usage: When used in most compounds or when counting a number of months with (m-lite, ja, sc=Jpan, ヶ, tr=ka), lang-lite, ja, sc=Jpan, 月 is pronounced m-lite, ja, sc=Jpan, げつ, tr=getsu. When used
11. counter. a month as a duration of time
12. counter. (possibly obsolete) month of the year
13. counter. Usage: When used in most compounds or when counting a number of months with (m-lite, ja, sc=Jpan, ヶ, tr=ka), lang-lite, ja, sc=Jpan, 月 is pronounced m-lite, ja, sc=Jpan, げつ, tr=getsu. When used
14. affix. moon
15. affix. month
16. affix. menstruation, menstrual cycle
17. n. (Kansai historical) during the Edo period, a low rank of low-end prostitute
(syn-lite, ja, sc=Jpan, 野暮, tr=yabo)