ahnentafel
A genealogical numbering system for listing a person's direct ancestors.
To avoid the difficulties caused by this inventive numbering, three basic numbering formats are widely accepted in genealogical circles: the ahnentafel system for ascending genealogies, and the Register and NGS Quarterly systems for […]
Where it comes from
Borrowed from German Ahnentafel (literally “ancestors table”).
Adapted from the Wiktionary entry ahnentafel (CC BY-SA 4.0).