From date +‎ stamp.

• Audio (US):

  (file)

datestamp (plural datestamps)

1. (computing) The date on which an event occurred, often included in a log to track the sequence of events.

• timestamp

datestamp (third-person singular simple present datestamps, present participle datestamping, simple past and past participle datestamped)

1. (transitive) To mark with a datestamp.