bran means: It is the tough outer coating of many types of grain kernels. This ingredient is used to supplement nutrient intake and marketing in cereal. (in Cooking Dictionary)

What else does bran mean?

A high amount of fiber is found in the outer husks of grain such as wheat. The bran is removed from white flour. Whole wheat flours can contain some or all of the bran. (in Cooking Dictionary)

These are the outer layers found just below the grain hull. Miller’s bran is formed during milling, when bran layers from the kernel of the grain are removed. Bran makes up about 14.5 percent in whole wheat flour. Bran can be used to increase dietary fiber, and other nutrients in cereals and baked goods. (in Cooking Dictionary)

The outer grains of grain cereals like wheat are removed in the milling process and can be used to provide dietary fiber. (in Merlin Dictionary)