The name Challah:
Bread in Hebrew is called Lechem while the separated dough is called Challah. It is customary to call the Shabbos bread Challah in order to serve as a reminder to women to separate Challah from the dough. In previous times, it was common in many communities to refer to the Shabbos bread as “Barchas.” The reason for this is because these Challahs serve as a channel of blessing during the Shabbos meal.
 Ashel Avraham [Butchach] 260
 Piskeiy Teshuvos 243 footnote 88