‘Leaven’, in contradistinction to matzah, ‘unleavened bread’. As recorded in the book of Exodus, chapter 12, no leaven must be eaten during the ‘feast of unleavened bread’, hag hamatzot.
On the night preceding the festival (the night belonging to the following day of 14 Nisan) the house is searched for hametz and any found is removed from the house. In addition, a declaration is made that any hametz that may have been overlooked is rendered null and void. This declaration and the whole procedure of searching for the hametz is found in all editions of the Passover Haggadah.
Subjects: Judaism and Jewish Studies.