Related Clues:

• ''It seemed like a good ___ at the time!''
• It's in your mind
• It may be bright or big
• "An __ is salvation by imagination": Frank Lloyd Wright
• Creative output
• Step one of an invention
• Mental inspiration
• Cranial bulb?
• "The very __!"
• Cartoon light bulb
• 'You have no ___'
• Creative inspiration
• Future invention
• What a germ may become
• It starts in your head