1. a mental process in which a set of memories or other mental representations is checked for the presence or absence of a particular target item. For example, one might search one’s memory for the name of a former teacher.

2. a task in which a person is asked to check an array of presented stimuli, or a previously memorized list of stimuli, to determine whether any of a set of target stimuli is in the array or list. See visual search. See also consistent mapping; varied mapping.

3. in problem solving, the process by which the solver attempts to find the correct answer or best solution from among a range of alternatives. See backward search; best-first search; exhaustive search; heuristic search; self-terminating search.

4. in artificial intelligence, the systematic investigation of states of a problem or game as part of finding a solution. There are multiple approaches to the search, including backtrack search, depth-first search, breadth-first search, and A* search, and many techniques are available for investigating the relevance of these approaches for different applications.