Matzah (מַצָּה): M-Tz-H, which means "to drain," "to squeeze out," or "to wring."

Draining blood from a sacrifice:

• "And the blood of the sin-offering shall be drained out (yimatzeh) at the base of the altar." (Leviticus 5:9)

• "And its blood shall be drained out (yimatzeh) on the side of the altar." (Leviticus 1:15)

Ancient Chag (Festival) of Spring:

"Observe the month of Aviv (Spring) and keep the Passover to the Lord your God, for in the month of Aviv the Lord your God brought you out of Egypt by night." (Deuteronomy 16:1) 

The Month: "The Month of Spring" (Aviv)

In the Torah, this month is not originally called "Nissan" (which is a later Babylonian name). It is called Chodesh HaAviv—literally "The Month of Spring" or "The Month of Ripening Barley."

• Scripture: "Observe the month of Aviv (Spring) and keep the Passover to the Lord your God, for in the month of Aviv the Lord your God brought you out of Egypt by night." (Deuteronomy 16:1)

Chag HaMatzot

While we often call it "Passover" today, the Torah distinguishes between the event and the festival (Chag):

• The Offering (Pesach): On the 14th day of the month (afternoon), the lamb was sacrificed. This was a ritual act, not yet the full festival.

• The Festival (Chag HaMatzot): On the 15th day (nightfall), the actual 7-day "Chag" begins.

  • Scripture: "And on the fifteenth day of the same month is the Feast of Unleavened Bread unto the Lord; seven days ye must eat unleavened bread." (Leviticus 23:6)

    
    

    Biblical Name	Day of Month (1st Month)	Event
    Pesach (Passover)	14th Day	Sacrifice of the Lamb (Preparation)
    Chag HaMatzot	15th - 21st Days	The Ancient Chag (Eating Unleavened Bread)
    Omer (First Fruits)	"Day after the Sabbath"	Barley Harvest Offering (Start of count to Shavuot)

    
    

    Tradition	Event	Type of "Fasting"
    Rabbinic	Ta'anit Bechorot	Daytime fast for firstborns (Nissan 14). To commemorate that the Israelite firstborns were saved from the 10th Plague (Death of the Firstborn) while the Egyptian firstborns died.
    Rabbinic	Erev Pesach	Prohibition on eating Matzah (to create hunger). Eating Matzah is a form of asceticism. It is flavorless and simple, mimicking the diet of a slave or a prisoner.
    Rabbinic	Afikoman	Fasting from food/drink after the Seder ends.
    Ethiopian	Sigd / Pre-Pesach	Elders historically fasted for purification before the holiday.  They historically observed a Fast of the Firstborn that was much stricter than the rabbinic version. Fast of the Elders: Some Ethiopian elders would fast for up to three days before Passover to purify themselves for the sacrifice (recalling the 3-day purification before Mt. Sinai).