To brainstorm is to think about and try to come up with ideas or solutions to a problem, either on your own or in a group.(verb)
If you and your co-workers sit around and try to come up with new ideas for an ad campaign, this is an example of when you brainstorm ideas.
The definition of a brainstorm is a sudden idea or plan.(noun)
When you suddenly come up with an idea for a new electronic device, seemingly out of nowhere, this is an example of a brainstorm.
See brainstorm in Webster's New World College Dictionary
See brainstorm in American Heritage Dictionary 4
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