brainstorm (n.) Look up brainstorm at Dictionary.com
also brain-storm, "brilliant idea, mental excitement, fit of mental application," 1849, from brain (n.) + figurative use of storm (n.). Also sometimes "mental disturbance" (1907). Verbal meaning "make a concerted attack on a problem, involving spontaneous ideas," is by 1947. Related: Brainstormed; brainstorming.