Related Clues:

• Straightedge
• One in charge
• Potentate
• Leader
• Back-to-school item
• Queen, e.g.
• Pencil-box accessory
• Rapper in class?
• Monarch
• King or queen, e.g.
• King or czar
• It's made to measure
• Measuring aid
• Measuring stick
• Measuring tool