Related Clues:

• Word on a dollar
• Hydrogen's number
• Aggravation, so to speak
• Area-code preceder
• Score on an aced hole
• Part of binary code
• Hour after noon
• Count starter
• Square __
• Countdown end
• White Monopoly bill
• Eagle's bill?
• It contains four quarters
• Number before 'Liftoff!'
• Bill in the till