A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day, sometimes accurate to a small fraction of a second.
A distinction is sometimes made between the terms datestamp, timestamp and date-timestamp: The term "timestamp" derives from rubber stamps used in offices to stamp the current date, and sometimes time, in ink on paper documents, to record when the document was received.
This data is usually presented in a consistent format, allowing for easy comparison of two different records and tracking progress over time; the practice of recording timestamps in a consistent manner along with the actual data is called timestamping.
Practically all computer file systems store one or more timestamps in the per-file metadata.
Without cleaning up inaccurate timestamps, time-related applications such as provenance analysis or pattern queries are not reliable.