Related Clues:

• The p in mph
• Smiling, probably
• "As ___ instructions"
• "Minute" or "hour" lead-in
• Feet-second connector
• One ___ person
• "Capita" go-with
• -- annum
• Parts ___ million
• The 'p' of mph
• "Diem" or "annum" preceder
• Middle of mph
• ___ curiam (like some court rulings)
• As-instructions link
• With 48 Across, nail-biting time