An instant can be defined at different level (known also as precision)
| Precision | Instant Name |
|---|---|
| year | |
| year-month | |
| year-month-day (such as an anniversary date) | date |
| year-month-day hour | |
| year-month-day hour:minute | |
| year-month-day hour:minute:second | datetime |
| year-month-day hour:minute:second.milliseconds | timestamp |
On a computer level, a date data type may be used to store time at the second level. (Example with java) You need to lookup the data type definition to known it's precision