Related Clues:

• 50%, up front?
• Of England
• Prefix with ''sphere''
• Natural prefix
• 'The Name of the Rose' author Umberto
• Vapor, in combinations
• It means half
• Saxon preceder
• Prefix with car
• Earth First prefix
• Author of 'The Island of the Day Before'
• Prefix with 'sphere'
• Fifty percent, up front?
• Prefix with ''friendly''
• "Foucault's Pendulum" author Umberto