Brainstorming refers to a group activity which allows people to generate ideas, raise questions, pose solutions, and reach agreement on issues concerning many individuals
Other /More definition:
Brainstorming refers to a method for enhancing creativity in groups that calls for heightened expressiveness, postponed evaluation, quantity rather than quality, and deliberate attempts to build on earlier ideas.
Brainstorming is a form of creative thinking in groups, using a procedure in which all group members are encouraged to generate as many ideas as possible
List of books: Brainstorming