For romantic interaction, please see date.
A date was a particular day on a calendar, usually meaning what event was due.
The date of a medical file was usually included in the file number. In 2364, Doctor Beverly Crusher determined from Mark Jameson's medical files that the test results he gave her were two months old, not two days, as he'd claimed. She therefore suspected he was lying, and shared her suspicions with Captain Jean-Luc Picard. (TNG: "Too Short A Season")