The word is "月".
This word has on-yomi and kun-yomi.
(If you don't know on-yomi and kun-yomi, please read a past entry of this blog!)
on-yomi : 月 / gatsu or getsu : =month
kun-yomi : 月 / tsuki : =moon
In Japanese language, 12 months are expressed by adding "月" to a number.
For example, January is "1月"(ichi-gatsu), and Febrary is "2月"(ni-gatsu).
On the other hand, if you want to express about period, for example, like a "one month" or "two months", you could use a word of "1ヶ月"(ikka-getsu) or "2ヶ月"(ni-ka-getsu).
*If you want to know about this kanji more, please leave comment on this blog!
