Challah bread is a traditional braided bread, and is very often the type of braided bread you will see sold on store shelves.
However, challah bread is more than a braided bread. It is steeped in religious history. Challah is a rich bread, made with eggs, that is traditionally baked every week for the Jewish sabbath (known as shabbat). Challah bread is also served for the Jewish New Year, or Rosh Hashana, which is starting soon. For this special time, the bread ingredients are changed a bit, for the addition of more sugar or honey.. for a sweet new year. Shaping is also changed from a long braid to a round braid.
The round challah represents the "round" year. It also symbolizes a crown, for crowning God as king. Traditional challahs are also shaped like ladders and keys. In some areas, the bread will be shaped to represent animals like swans, lions or gazelles.
To learn more about this interesting bread, take a look at the links below:
http://www.npr.org/blogs/thesalt/2014/09/23/350890028/rosh-hashanas-sacred-bread-offers-meaning-in-many-shapes-and-sizes
http://www.examiner.com/article/traditional-challah-bread-and-it-s-beautiful-history
http://www.kingarthurflour.com/blog/2009/01/05/challa-lujah/
http://sdjewishjournal.com/site/1048/the-magic-of-challah/