Hi Cassy,
it's NAV speak for something with "posted" tables, but not ledger entries or registers. For example, invoices can be entered in the the invoice form/page, where you can print it more or less nicely formatted after posting it. You can send it to someone, for instance. You could also post an invoice in a Sales Journal. Then you have only ledger entries and registers, no "document" after posting. To reverse those, you could use the "Reverse Transaction" function.
with best regards
Jens