Matza (also Matzah Hebrew מַצָּה, in Ashkenazi matzo or matzoh, and in Yiddish, matze, Greek - "Masa", or "Massa") is a cracker-like bread made of white plain flour, and water. The dough is pricked in several places and not allowed to rise before or during baking, thereby producing a hard, flat bread.Matza is the substitute for bread during the Jewish holiday of Passover, when eating chametz - bread and leavened products - is forbidden. Eating matza on the night of the seder is considered a positive mitzvah, i.e., a commandment.There are numerous explanations behind the meaning of matza. One is historical: Passover is a commemoration of the exodus from Egypt. The biblical narrative relates that the Israelites left Egypt in such haste, they could not wait for their bread dough to rise. The resulting product was matza. (Exodus 12:39). The other reason for eating matza is symbolic: On the one hand, matza symbolizes redemption and freedom, but it is also (lechem oni), "poor man's bread." Thus it serves as a reminder to be humble, and to not forget what life was like in servitude. Eating the "bread of affliction" is both a lesson in humility and an act that enhances one's appreciation of freedom.At the Passover seder, it is customary to eat matza made of flour and water only. Matza containing eggs, wine or fruit juice in addition to water is not acceptable as it is considered to become leaven. Matza made with these items without the use of water is acceptable during the remaining days of the holiday, although some strictly Orthodox Jews will not eat this kind of matza at all.After baking, matza may be ground into fine crumbs, known as matza meal. Matza meal is used to make matza balls and is added to other foods, such as gefilte fish, to hold the ingredients together instead of flour. Kosher for Passover cakes and cookies are made with matza meal, which gives them a denser texture than ordinary baked goods made with flour.There are five grains that may not be used during Passover in any form except matzoh.Wheat,Barley,Spelt,Rye, andOats (according to Rashi) (or two-rowed barley according to Rambam's interpretation of Mishnah Kilayim 1:1; Yerushalmi Challah 1:1).Wheat and spelt (biblical spelt is now more correctly identified as emmer wheat) are both in the genus Triticum and anything else in the genus is likewise forbidden. Oat-grain is practically gluten-free and belongs to a different tribe than wheat, spelt, rye and barley. Millet and teff are borderline; it takes a few days for them to rise.Dough made from the five grains is considered to begin the leavening process 18 minutes from the time it gets wet, and sooner if eggs, fruit juice or milk is added to the dough. In reality, though, the entire process of making a matzoh takes only a few minutes in efficient, well-organized modern matzo bakeries.Matzoh can be ground to form coarse (matzoh farfel), medium, or fine matzoh meal, used in Jewish cooking and as a substitute for flour in Passover cooking.