A new moon refers to the moon when its phase is 0, a waxing moon refers to the moon when its phase is 7.5, a full moon refers to the moon when its phase is 14 and a waning moon refers to the moon when its phase is 22.5.
月齢は0が新月、7.5が上弦の月、14が満月、22.5が下弦の月である。