breadth-first search
a graph search strategy that considers states in a graph recursively: If the present state is not the goal state, then its sibling state is considered. If this sibling is not the goal state, then its sibling is considered. If there are no more siblings, then the first child of the first state is considered. This process continues until either a goal state is found or there are no further states to examine. States, their siblings, and their children are usually considered in a left-to-right format. Breadth-first search is often organized by a “queue” or “first-in is first-out” data structure.