In breadth first search of a search tree, one prgresses by first of all looking at all of the nodes at level 1 (one step from the root), then all the nodes at level 2, etc.
Used in Chap. 4: pages 43, 44, 45, 46, 47, 48, 50, 53, 54; Chap. 11: page 152; Chap. 15: page 223
Also known as breadth first, breadth first
Breadth first search – order of visiting nodes