noun
moon radical on the left
Refers to the kanji component 月 when it appears on the left side of a character. Often called radical 130, but note that the same shape can also represent the 'flesh' radical (肉月).
See also: 肉月
「明」の左側は月偏です。
The left side of 明 is the moon radical.
月偏と肉月は形が同じなので注意が必要です。
The moon radical and the flesh radical look the same, so you need to be careful.