訓 つき ・ 音 ゲツ,ガツ
漢越音: nguyệt
A crescent moon with two lines across it. One full cycle of that moon equals one month, which is why it means both.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
来月日本へ行きます。 (らいげつにほんへいきます)
I will go to Japan next month.