Possible Clues:

• Tiny time meas
• Tiny fraction of a min
• One 60-trillionth of a min
• 1/60 of a trillionth of a min.
• Infinitesimal division of a min.
• One 60-trillionth of a min.
• Min. fraction
• Time unit for studying the speed of light: Abbr.
• Tiny fraction of a min.
• There are 60 trillion in a min.