Signalement is the physical description. You can often find signalementen in military records, prison records, or in police bulletins. It is rare to find a physical description for ancestors before say 1800.
See a list of Dutch terms in physical descriptions for more information.
This is so interesting! I also found a description for my great great grandfather…. but how do I understand/convert his height of 1 El 634 strepen? I have been unable to find any useful modern comparison.