Related Clues:

• Sundial letters
• It's at the top of a face
• See 39-Across
• Twelve
• Clock numeral
• Midnight, on a grandfather's clock
• Hour on a clock
• It's atop a face
• Top of a dial
• Clock number
• Noon in Old Rome
• Cato's lunch hour
• Noon, in old Rome
• Sundial number
• Sundial numeral