A royement can have multiple meanings, all having to do with cancellation or ceasing to be valid. When referring to persons, it is a disbarment or revoking of membership. When referring to records, it means the record itself is cancelled, for example when a mortgage is paid.
You may come across the term in contemporary summaries of notarial records. Royementen of mortgages were typically created and handed to the interested party, rather than also being copied into the notaries’ minutes. The reference in the contemporary summary may be all the evidence you find.