Related Clues:

• 'What's the big --?'
• It's all in your head
• It has a germ
• Brain trust offering
• Vision
• The light bulb, to Edison
• "The very ___!"
• Flash of brilliance
• Postulation
• Creative thought
• It may be seminal
• Thesis basis
• Fanciful notion
• Brainstorming session result
• Bean concoction?