'Moon' in the Bible

So David told him, “Look, tomorrow is the New Moon, and I’m supposed to sit down and eat with the king. Instead, let me go, and I’ll hide in the field until the third night.

Then Jonathan said to him, “Tomorrow is the New Moon; you’ll be missed because your seat will be empty.

So David hid in the field.At the New Moon, the king sat down to eat the meal.

However, the day after the New Moon, the second day, David’s place was still empty, and Saul asked his son Jonathan, “Why didn’t Jesse’s son come to the meal either yesterday or today?”

He got up from the table in fierce anger and did not eat any food that second day of the New Moon, for he was grieved because of his father’s shameful behavior toward David.