Why the special name--challah--for the bread we eat on Shabbat?
Challah is the Hebrew word for the portion of dough given to the kohens (priests) in the times of the Holy Temple. Today, a small amount of dough is burnt in remembrance. By using the word "challah" we are reminded of this ancient obligation. Also, the word "challah" is almost identical with the Hebrew word "kallah"--bride. Since Shabbat is called our "bride," the bread that we eat on Shabbat is called challah.