Related Clues:

• ''Hey, what's the big ___?''
• Gray matter creation
• Patent basis
• Pavarotti or Domingo, e.g.
• Carreras, for one
• Content of cognition
• ''What's the bright ___?''
• Asset for an entrepreneur
• Result of cogitating, perhaps
• Piece of mind?
• Seed of invention
• What may come to mind
• Just think of it
• Prelude to a solution
• Central theme