yuè

The moon, is the radical, No.74. A picture of the crescent moon completely visible (compare 夕 xī No. 14)

The word for moon is shaped like a crescent. Also means month since ancient calendar are based on the lunar cycle.
Compounds
月饼 yuèbǐng – moon cake
月亮 yuèliang – moon
月票 yuèpiào – monthly ticket (buspass, train ticket, etc.)

Months of the year

一月 yīyuè – January
二月 èryuè – February
三月 sānyuè – March
四月 sìyuè – April
五月 wŭyuè – May
六月 liùyuè – June
七月 qīyuè – July
八月 bāyuè – August
九月 jiŭyuè – September
十月 shíyuè – October
十一月 shíyīyuè – November
十二月 shíèryuè – December

Learn more about 月 at Wikionary