Do not confuse 月 with ⺼, a form of 肉 (“flesh, meat”) when used as the left-hand radical of a character. ⺼ is used for parts of the body such as 背 (“back”) or 肝 (“liver”). These may be written identically as 月, but in careful use they are distinguished, with the inside of ⺼ being written with unattached diagonal strokes. This is particularly an issue in looking up characters by radical; compare the 月 index and 肉 index.
When used in compounds counting a number of months with "ヶ"(か, ka), 月 is pronounced as げつ (getsu). When used in compounds for modern months of the year, it is pronounced as がつ (gatsu). When used for poetic or lunar months, it is pronounced as つき (tsuki).