#picosecond  one trillionth of a second; one thousandth of a nanosecond
  supertype:  time_unit__unit_of_time  a unit for measuring time periods
  part of:  nanosecond
  part:  femtosecond  one quadrillionth of a second; one thousandth of a nanosecond
     part:  attosecond  one quintillionth of a second; one thousandth of a femtosecond

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