Uniquness of ctid

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/15/ddl-system-columns.html
Description:

Hi,
Looking at the explanation abour ctid, it is "The physical location of the
row version within its table. "
From that line, I think ctid is unique in the table.
And I also think ctid might be unique across the database since it is the
physical location.
But I was not sure about this.
Please confirm if my assumption is right or not.

Thanks
Brian