How is field 'Updated' calculated?

[Gaurav Guliani]

Hi JIRA experts,

I'm new to JIRA and looking to understand how column 'Updated' in JIRA reports work?
Is it the time when last update was made to the ticket or it is an formula driven field based on when it was last resolved?
For example: If I mark a ticket as resolved on 1st Jan 2021 at 9 am. Would updated column automatically become 1st Jan 2021 at 9 am as well? And now if the creator responds saying 'Thanks' to the resolved ticket on 2nd Jan 2021 at 10 am, would the updated column finally show

- 2nd Jan 2021 at 10 am, or

- 4th Jan 2021 at 9 am (Based on closed status being equal to Resolved + 3 days)

Please suggest

[Nic Brough -Adaptavist-]

It is the last time an issue was amended - transition, edit, comment, whatever the change.

[Matt Doar]

Resolution Date is set when the system Resolution field gets a value added.

Updated date does not include when watchers or voters are added. Otherwise, as Nic says, it's any other change