Possible Clues:

• Millionth of a metre
• Millionth of a meter
• One millionth of a meter
• One millionth of a metre
• .000001 meters
• One-millionth of a meter
• Thousandth of a millimeter
• One-millionth of a metre
• Greek character with no head and hardly any length
• Sounds as if Ronald follows Michael in short measure